diff --git a/code/__DEFINES/dcs/signals/signals.dm b/code/__DEFINES/dcs/signals/signals.dm
index b13f9720def45..09f5e157bb96c 100644
--- a/code/__DEFINES/dcs/signals/signals.dm
+++ b/code/__DEFINES/dcs/signals/signals.dm
@@ -726,6 +726,11 @@
 
 #define COMSIG_XENOMORPH_LEAP_BUMP "xenomorph_leap_bump" //from /mob/living/carbon/xenomorph/bump
 
+// Xeno upgrade chambers
+#define COMSIG_UPGRADE_CHAMBER_SURVIVAL "upgrade_chamber_survival"
+#define COMSIG_UPGRADE_CHAMBER_ATTACK "upgrade_chamber_attack"
+#define COMSIG_UPGRADE_CHAMBER_UTILITY "upgrade_chamber_utility"
+
 //human signals
 #define COMSIG_CLICK_QUICKEQUIP "click_quickequip"
 
diff --git a/code/__DEFINES/mobs.dm b/code/__DEFINES/mobs.dm
index 0cd074464345b..187fbc071615f 100644
--- a/code/__DEFINES/mobs.dm
+++ b/code/__DEFINES/mobs.dm
@@ -589,12 +589,13 @@ GLOBAL_LIST_INIT(layers_to_offset, list(
 #define CASTE_STAGGER_RESISTANT (1<<15) //Resistant to some forms of stagger, such as projectiles
 #define CASTE_HAS_WOUND_MASK (1<<16) //uses an alpha mask for wounded states
 #define CASTE_EXCLUDE_STRAINS (1<<17) // denotes castes/basetypes that should be excluded from being evoable as a strain
+#define CASTE_NO_BIOMASS (1<<18) // Xenos are excluded from getting any biomass
 
 // Xeno defines that affect evolution, considering making a new var for these
-#define CASTE_LEADER_TYPE (1<<16) //Whether we are a leader type caste, such as the queen, shrike or ?king?, and is affected by queen ban and playtime restrictions
-#define CASTE_CANNOT_EVOLVE_IN_CAPTIVITY (1<<17) //Whether we cannot evolve in the research lab
-#define CASTE_REQUIRES_FREE_TILE (1<<18) //Whether we require a free tile to evolve
-#define CASTE_INSTANT_EVOLUTION (1<<19) //Whether we require no evolution progress to evolve to this caste
+#define CASTE_LEADER_TYPE (1<<19) //Whether we are a leader type caste, such as the queen, shrike or ?king?, and is affected by queen ban and playtime restrictions
+#define CASTE_CANNOT_EVOLVE_IN_CAPTIVITY (1<<20) //Whether we cannot evolve in the research lab
+#define CASTE_REQUIRES_FREE_TILE (1<<21) //Whether we require a free tile to evolve
+#define CASTE_INSTANT_EVOLUTION (1<<22) //Whether we require no evolution progress to evolve to this caste
 
 #define CASTE_CAN_HOLD_FACEHUGGERS (1<<0)
 #define CASTE_CAN_BE_QUEEN_HEALED (1<<1)
diff --git a/code/__DEFINES/movespeed_modification.dm b/code/__DEFINES/movespeed_modification.dm
index b8e4deeb20b35..b72ed7d134eae 100644
--- a/code/__DEFINES/movespeed_modification.dm
+++ b/code/__DEFINES/movespeed_modification.dm
@@ -32,6 +32,7 @@
 #define MOVESPEED_ID_WARLOCK_CHANNELING "WARLOCK_CHANNELING"
 #define MOVESPEED_ID_XENO_DREAD "DREADXENO"
 #define MOVESPEED_ID_BEHEMOTH_PRIMAL_WRATH "BEHEMOTH_PRIMAL_WRATH"
+#define MOVESPEED_ID_CELERITY_BUFF "UPGRADE_CHAMBER_CELERITY_BUFF"
 #define MOVESPEED_ID_PRAETORIAN_DANCER_DODGE_SPEED "PRAETORIAN_DANCER_DODGE_SPEED"
 
 #define MOVESPEED_ID_SIMPLEMOB_VARSPEED "SIMPLEMOB_VARSPEED_MODIFIER"
diff --git a/code/__DEFINES/status_effects.dm b/code/__DEFINES/status_effects.dm
index 64fb57c8ba1af..dead66ff61e43 100644
--- a/code/__DEFINES/status_effects.dm
+++ b/code/__DEFINES/status_effects.dm
@@ -39,6 +39,24 @@
 
 #define STATUS_EFFECT_DRAIN_SURGE /datum/status_effect/drain_surge
 
+#define STATUS_EFFECT_UPGRADE_CARAPACE /datum/status_effect/mutation_upgrade/carapace
+
+#define STATUS_EFFECT_UPGRADE_REGENERATION /datum/status_effect/mutation_upgrade/regeneration
+
+#define STATUS_EFFECT_UPGRADE_VAMPIRISM /datum/status_effect/mutation_upgrade/vampirism
+
+#define STATUS_EFFECT_UPGRADE_CELERITY /datum/status_effect/mutation_upgrade/celerity
+
+#define STATUS_EFFECT_UPGRADE_ADRENALINE /datum/status_effect/mutation_upgrade/adrenaline
+
+#define STATUS_EFFECT_UPGRADE_CRUSH /datum/status_effect/mutation_upgrade/crush
+
+#define STATUS_EFFECT_UPGRADE_TOXIN /datum/status_effect/mutation_upgrade/toxin
+
+#define STATUS_EFFECT_UPGRADE_PHERO /datum/status_effect/mutation_upgrade/pheromones
+
+#define STATUS_EFFECT_UPGRADE_TRAIL /datum/status_effect/mutation_upgrade/trail
+
 #define STATUS_EFFECT_MINDMEND /datum/status_effect/mindmeld
 
 #define STATUS_EFFECT_REKNIT_FORM /datum/status_effect/reknit_form
diff --git a/code/__DEFINES/xeno.dm b/code/__DEFINES/xeno.dm
index 87a0bec6b1ff7..b2138bf600d50 100644
--- a/code/__DEFINES/xeno.dm
+++ b/code/__DEFINES/xeno.dm
@@ -92,6 +92,14 @@ GLOBAL_LIST_INIT(defiler_toxin_type_list, list(
 	/datum/reagent/toxin/xeno_ozelomelyn,
 ))
 
+//List of Defiler toxin images
+GLOBAL_LIST_INIT(defiler_toxin_images_list, list(
+	DEFILER_OZELOMELYN = image('icons/Xeno/actions/defiler.dmi', icon_state = DEFILER_OZELOMELYN),
+	DEFILER_HEMODILE = image('icons/Xeno/actions/defiler.dmi', icon_state = DEFILER_HEMODILE),
+	DEFILER_TRANSVITOX = image('icons/Xeno/actions/defiler.dmi', icon_state = DEFILER_TRANSVITOX),
+	DEFILER_NEUROTOXIN = image('icons/Xeno/actions/defiler.dmi', icon_state = DEFILER_NEUROTOXIN)
+))
+
 //List of toxins improving defile's damage
 GLOBAL_LIST_INIT(defiler_toxins_typecache_list, typecacheof(list(
 	/datum/reagent/toxin/xeno_ozelomelyn,
@@ -210,3 +218,31 @@ GLOBAL_LIST_INIT(xeno_ai_spawnable, list(
 
 /// Life runs every 2 seconds, but we don't want to multiply all healing by 2 due to seconds_per_tick
 #define XENO_PER_SECOND_LIFE_MOD 0.5
+
+// Mutations
+GLOBAL_DATUM_INIT(mutation_selector, /datum/mutation_datum, new)
+
+GLOBAL_LIST_INIT(mutation_upgrades_buyable, list(
+	/datum/mutation_upgrade/survival/carapace,
+	/datum/mutation_upgrade/survival/regeneration,
+	/datum/mutation_upgrade/survival/vampirism,
+	/datum/mutation_upgrade/attack/celerity,
+	/datum/mutation_upgrade/attack/adrenaline,
+	/datum/mutation_upgrade/attack/crush,
+	/datum/mutation_upgrade/utility/toxin,
+	/datum/mutation_upgrade/utility/pheromones,
+	/datum/mutation_upgrade/utility/trail
+))
+
+#define MUTATION_CATEGORY_SURVIVAL "Survival"
+#define MUTATION_CATEGORY_ATTACK "Attack"
+#define MUTATION_CATEGORY_UTILITY "Utility"
+
+#define MUTATION_STRUCTURE_CHAMBER "shell"
+#define MUTATION_STRUCTURE_SPUR "spur"
+#define MUTATION_STRUCTURE_VEIL "veil"
+
+#define	XENO_UPGRADE_BIOMASS_COST_T1 15
+#define	XENO_UPGRADE_BIOMASS_COST_T2 20
+#define	XENO_UPGRADE_BIOMASS_COST_T3 25
+#define	XENO_UPGRADE_BIOMASS_COST_T4 30
diff --git a/code/datums/status_effects/xeno_buffs.dm b/code/datums/status_effects/xeno_buffs.dm
index 696be4748dbfe..5232216ef5c1b 100644
--- a/code/datums/status_effects/xeno_buffs.dm
+++ b/code/datums/status_effects/xeno_buffs.dm
@@ -871,3 +871,469 @@
 	xeno_owner.xeno_melee_damage_modifier -= modifier
 	xeno_owner.remove_filter("frenzy_screech_outline")
 	return ..()
+
+// ***************************************
+// *********** Upgrade Chambers Buffs
+// ***************************************
+/datum/status_effect/mutation_upgrade
+	/// Owner typed as an xenomorph.
+	var/mob/living/carbon/xenomorph/buff_owner
+	/// The structure to base chamber_scaling on.
+	var/chamber_structure
+	/// The amount of times to multiply the main effect by.
+	var/chamber_scaling = 0
+
+/datum/status_effect/mutation_upgrade/on_apply()
+	if(!isxeno(owner))
+		return FALSE
+	buff_owner = owner
+	update_chamber_scaling()
+	return TRUE
+
+/// Sets the chamber_scaling based on the amount of chambers in the xeno's hive.
+/datum/status_effect/mutation_upgrade/proc/update_chamber_scaling()
+	switch(chamber_structure)
+		if(MUTATION_STRUCTURE_CHAMBER)
+			chamber_scaling = length(buff_owner.hive?.shell_chambers)
+		if(MUTATION_STRUCTURE_SPUR)
+			chamber_scaling = length(buff_owner.hive?.spur_chambers)
+		if(MUTATION_STRUCTURE_VEIL)
+			chamber_scaling = length(buff_owner.hive?.veil_chambers)
+
+// ***************************************
+// *********** Upgrade Chambers Buffs - Survival
+// ***************************************
+/atom/movable/screen/alert/status_effect/carapace
+	name = "Carapace"
+	desc = "Armor increased."
+	icon_state = "xenobuff_carapace"
+
+/datum/status_effect/mutation_upgrade/carapace
+	id = "mutation_upgrade_carapace"
+	alert_type = /atom/movable/screen/alert/status_effect/carapace
+	chamber_structure = MUTATION_STRUCTURE_CHAMBER
+	/// The amount of soft armor given.
+	var/armor_buff_per_chamber = 2.5
+
+/datum/status_effect/mutation_upgrade/carapace/on_apply()
+	if(!..())
+		return FALSE
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_SURVIVAL, PROC_REF(update_buff))
+	buff_owner.soft_armor = buff_owner.soft_armor.modifyAllRatings(armor_buff_per_chamber * chamber_scaling)
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/carapace/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_SURVIVAL)
+	buff_owner.soft_armor = buff_owner.soft_armor.modifyAllRatings(-armor_buff_per_chamber * chamber_scaling)
+	return ..()
+
+/// Sets the chamber_scaling to the amount of active survival chambers and adjusts soft armor accordingly.
+/datum/status_effect/mutation_upgrade/carapace/proc/update_buff()
+	SIGNAL_HANDLER
+	buff_owner.soft_armor = buff_owner.soft_armor.modifyAllRatings(armor_buff_per_chamber * (length(buff_owner.hive.shell_chambers) - chamber_scaling))
+	update_chamber_scaling()
+
+
+// ***************************************
+// ***************************************
+// ***************************************
+/atom/movable/screen/alert/status_effect/regeneration
+	name = "Regeneration"
+	desc = "Regeneration increased."
+	icon_state = "xenobuff_regeneration"
+
+/datum/status_effect/mutation_upgrade/regeneration
+	id = "mutation_upgrade_regeneration"
+	alert_type = /atom/movable/screen/alert/status_effect/regeneration
+	chamber_structure = MUTATION_STRUCTURE_CHAMBER
+	/// The amount of max health to be regenerated everytime the proc 'heal_wounds' is called.
+	var/health_regen_per_chamber = 0.008 // 0.8%
+	/// The amount of sunder to be regenerated everytime the proc 'heal_wounds' is called.
+	var/sunder_regen_per_chamber = 0.166
+
+/datum/status_effect/mutation_upgrade/regeneration/on_apply()
+	if(!..())
+		return FALSE
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_SURVIVAL, PROC_REF(update_buff))
+	RegisterSignal(buff_owner, COMSIG_XENOMORPH_HEALTH_REGEN, PROC_REF(on_heal_wounds))
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/regeneration/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_SURVIVAL)
+	UnregisterSignal(buff_owner, COMSIG_XENOMORPH_HEALTH_REGEN)
+	return ..()
+
+/// Sets the chamber_scaling to the amount of active survival chambers.
+/datum/status_effect/mutation_upgrade/regeneration/proc/update_buff()
+	SIGNAL_HANDLER
+	update_chamber_scaling()
+
+/// Heals the xenomorph's health and sunder based on assigned variables.
+/datum/status_effect/mutation_upgrade/regeneration/proc/on_heal_wounds(mob/living/carbon/xenomorph/source_xenomorph, heal_data, seconds_per_tick)
+	SIGNAL_HANDLER
+	if(!chamber_scaling)
+		return
+	var/health_amount = buff_owner.maxHealth * health_regen_per_chamber * chamber_scaling
+	var/sunder_amount = -sunder_regen_per_chamber * chamber_scaling
+	HEAL_XENO_DAMAGE(buff_owner, health_amount, FALSE)
+	buff_owner.adjust_sunder(sunder_amount)
+	buff_owner.updatehealth()
+
+// ***************************************
+// ***************************************
+// ***************************************
+/atom/movable/screen/alert/status_effect/vampirism
+	name = "Vampirism"
+	desc = "Leech from attacks."
+	icon_state = "xenobuff_vampirism"
+
+/datum/status_effect/mutation_upgrade/vampirism
+	id = "mutation_upgrade_vampirism"
+	alert_type = /atom/movable/screen/alert/status_effect/vampirism
+	chamber_structure = MUTATION_STRUCTURE_CHAMBER
+	/// The amount of max health to be regenerated the owner hits an alive human.
+	var/leech_buff_per_chamber = 0.016
+
+/datum/status_effect/mutation_upgrade/vampirism/on_apply()
+	if(!..())
+		return FALSE
+	// Ravagers gets half of the effect since they eventually get their own version of vampirism.
+	if(isxenoravager(buff_owner))
+		chamber_scaling /= 2
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_SURVIVAL, PROC_REF(update_buff))
+	RegisterSignal(buff_owner, COMSIG_XENOMORPH_ATTACK_LIVING, PROC_REF(on_slash))
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/vampirism/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_SURVIVAL)
+	UnregisterSignal(buff_owner, COMSIG_XENOMORPH_ATTACK_LIVING)
+	return ..()
+
+/// Sets the chamber_scaling to the amount of active survival chambers.
+/datum/status_effect/mutation_upgrade/vampirism/proc/update_buff()
+	SIGNAL_HANDLER
+	update_chamber_scaling()
+	if(isxenoravager(buff_owner))
+		chamber_scaling /= 2
+
+/// Heals the xenomorph for hitting a non-dead human by a percentage of their max health.
+/datum/status_effect/mutation_upgrade/vampirism/proc/on_slash(datum/source, mob/living/target)
+	SIGNAL_HANDLER
+	if(target.stat == DEAD || !ishuman(target))
+		return
+	var/health_amount = buff_owner.maxHealth * leech_buff_per_chamber * chamber_scaling
+	HEAL_XENO_DAMAGE(buff_owner, health_amount, FALSE)
+	buff_owner.updatehealth()
+
+// ***************************************
+// *********** Upgrade Chambers Buffs - Attack
+// ***************************************
+/atom/movable/screen/alert/status_effect/celerity
+	name = "Celerity"
+	desc = "Run faster."
+	icon_state = "xenobuff_attack"
+
+/datum/status_effect/mutation_upgrade/celerity
+	id = "mutation_upgrade_celerity"
+	alert_type = /atom/movable/screen/alert/status_effect/celerity
+	chamber_structure = MUTATION_STRUCTURE_SPUR
+	/// The amount of movement speed the owner get.
+	var/speed_buff_per_chamber = 0.05
+
+/datum/status_effect/mutation_upgrade/celerity/on_apply()
+	if(!..())
+		return FALSE
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_ATTACK, PROC_REF(update_buff))
+	buff_owner.add_movespeed_modifier(MOVESPEED_ID_CELERITY_BUFF, TRUE, 0, NONE, TRUE, -speed_buff_per_chamber * chamber_scaling)
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/celerity/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_ATTACK)
+	buff_owner.remove_movespeed_modifier(MOVESPEED_ID_CELERITY_BUFF)
+	return ..()
+
+/// Sets the chamber_scaling to the amount of active spur chambers and adjusts movement speed accordingly.
+/datum/status_effect/mutation_upgrade/celerity/proc/update_buff()
+	SIGNAL_HANDLER
+	update_chamber_scaling()
+	buff_owner.add_movespeed_modifier(MOVESPEED_ID_CELERITY_BUFF, TRUE, 0, NONE, TRUE, -speed_buff_per_chamber * chamber_scaling)
+
+// ***************************************
+// ***************************************
+// ***************************************
+/atom/movable/screen/alert/status_effect/adrenaline
+	name = "Adrenaline"
+	desc = "Regenerate plasma."
+	icon_state = "xenobuff_attack"
+
+/datum/status_effect/mutation_upgrade/adrenaline
+	id = "mutation_upgrade_adrenaline"
+	alert_type = /atom/movable/screen/alert/status_effect/adrenaline
+	chamber_structure = MUTATION_STRUCTURE_SPUR
+	/// The amount of plasma to regenerate based on their caste's plasma regeneration.
+	var/plasma_regen_buff_per_chamber = 0.1 // 10%
+	/// The amount of plasma to regenerate based on their caste's maximum plasma.
+	var/plasma_percentage_buff_per_chamber = 0.01 // 1%
+
+/datum/status_effect/mutation_upgrade/adrenaline/on_apply()
+	if(!..())
+		return FALSE
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_ATTACK, PROC_REF(update_buff))
+	RegisterSignal(buff_owner, COMSIG_XENOMORPH_PLASMA_REGEN, PROC_REF(on_plasma_regen))
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/adrenaline/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_ATTACK)
+	UnregisterSignal(buff_owner, COMSIG_XENOMORPH_PLASMA_REGEN)
+	return ..()
+
+/// Sets the chamber_scaling to the amount of active spur chambers.
+/datum/status_effect/mutation_upgrade/adrenaline/proc/update_buff()
+	SIGNAL_HANDLER
+	update_chamber_scaling()
+
+/// Gives the xenomorph more plasma (according to their plasma regeneration and adjusted maximum) everytime they are suppose to regen plasma.
+/datum/status_effect/mutation_upgrade/adrenaline/proc/on_plasma_regen(mob/living/carbon/xenomorph/source_xenomorph, plasma_mod, seconds_per_tick)
+	SIGNAL_HANDLER
+	if(!chamber_scaling)
+		return
+	var/adjusted_plasma_max = buff_owner.xeno_caste.plasma_max * buff_owner.xeno_caste.plasma_regen_limit
+	var/plasma_regen_amount = buff_owner.xeno_caste.plasma_gain * plasma_regen_buff_per_chamber * chamber_scaling
+	var/plasma_max_amount = adjusted_plasma_max * plasma_percentage_buff_per_chamber * chamber_scaling
+	var/plasma_to_give = plasma_regen_amount + plasma_max_amount * ((buff_owner.resting || buff_owner.lying_angle) ? 2 : 1)
+	var/plasma_stored_predicted = (buff_owner.plasma_stored + plasma_to_give)
+	// Give only enough plasma to reach the adjusted amount (for castes like Hivelord).
+	buff_owner.gain_plasma(plasma_stored_predicted > adjusted_plasma_max ? plasma_stored_predicted - adjusted_plasma_max : plasma_to_give)
+
+// ***************************************
+// ***************************************
+// ***************************************
+/atom/movable/screen/alert/status_effect/crush
+	name = "Crush"
+	desc = "Additional damage to objects."
+	icon_state = "xenobuff_attack"
+
+/datum/status_effect/mutation_upgrade/crush
+	id = "mutation_upgrade_crush"
+	alert_type = /atom/movable/screen/alert/status_effect/crush
+	chamber_structure = MUTATION_STRUCTURE_SPUR
+	/// The bonus damage to deal as percentage.
+	var/damage_buff_per_chamber = 0.333 // 33.3%
+	/// The armour pentration the damage damage has.
+	var/penetration_buff_per_chamber = 10
+
+/datum/status_effect/mutation_upgrade/crush/on_apply()
+	if(!..())
+		return FALSE
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_ATTACK, PROC_REF(update_buff))
+	RegisterSignal(buff_owner, COMSIG_XENOMORPH_ATTACK_OBJ, PROC_REF(on_obj_attack))
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/crush/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_ATTACK)
+	UnregisterSignal(buff_owner, COMSIG_XENOMORPH_ATTACK_OBJ)
+	return ..()
+
+/// Sets the chamber_scaling to the amount of active spur chambers.
+/datum/status_effect/mutation_upgrade/crush/proc/update_buff()
+	SIGNAL_HANDLER
+	update_chamber_scaling()
+
+/// Deals bonus damage along with armour pentration to the object.
+/datum/status_effect/mutation_upgrade/crush/proc/on_obj_attack(datum/source, obj/attacked)
+	SIGNAL_HANDLER
+	if(!chamber_scaling)
+		return
+	if(attacked.resistance_flags & XENO_DAMAGEABLE)
+		var/adjusted_armour_penetration = penetration_buff_per_chamber * chamber_scaling
+		var/adjusted_damage = buff_owner.xeno_caste.melee_damage * damage_buff_per_chamber * chamber_scaling
+		var/expected_damage = round(attacked.modify_by_armor(adjusted_damage, MELEE, adjusted_armour_penetration, null, null), DAMAGE_PRECISION)
+		var/expected_integrity = max(attacked.obj_integrity - expected_damage, 0)
+		// Since this signal is called before they actually attack themselves, we do just enough so the main attack does the finishing blow.
+		if(!expected_integrity)
+			attacked.take_damage(expected_integrity - 0.1, BRUTE, MELEE, FALSE, armour_penetration = 100)
+			return
+		attacked.take_damage(buff_owner.xeno_caste.melee_damage * damage_buff_per_chamber * chamber_scaling, BRUTE, MELEE, FALSE, armour_penetration = (penetration_buff_per_chamber * chamber_scaling))
+
+// ***************************************
+// *********** Upgrade Chambers Buffs - Utility
+// ***************************************
+/atom/movable/screen/alert/status_effect/toxin
+	name = "Toxin"
+	desc = "Inject toxin on attack. Click to change toxin."
+	icon_state = "xenobuff_generic"
+
+/atom/movable/screen/alert/status_effect/toxin/Click()
+	var/datum/status_effect/mutation_upgrade/toxin/status_effect = attached_effect
+	var/datum/reagent/toxin/toxin_choice = show_radial_menu(status_effect.buff_owner, status_effect.buff_owner, GLOB.defiler_toxin_images_list, radius = 35, require_near = TRUE)
+	if(!toxin_choice)
+		return
+	for(var/defiler_toxin in GLOB.defiler_toxin_type_list)
+		var/datum/reagent/reagent = GLOB.chemical_reagents_list[defiler_toxin]
+		if(reagent.name == toxin_choice)
+			status_effect.selected_reagent = reagent.type
+			break
+	status_effect.buff_owner.balloon_alert(status_effect.buff_owner, "[toxin_choice]")
+
+/datum/status_effect/mutation_upgrade/toxin
+	id = "mutation_upgrade_toxin"
+	alert_type = /atom/movable/screen/alert/status_effect/toxin
+	chamber_structure = MUTATION_STRUCTURE_VEIL
+	/// Currently selected reagent to inject.
+	var/datum/reagent/toxin/selected_reagent = /datum/reagent/toxin/xeno_neurotoxin
+
+/datum/status_effect/mutation_upgrade/toxin/on_apply()
+	if(!..())
+		return FALSE
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_UTILITY, PROC_REF(update_buff))
+	RegisterSignal(buff_owner, COMSIG_XENOMORPH_ATTACK_LIVING, PROC_REF(on_slash))
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/toxin/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_UTILITY)
+	UnregisterSignal(buff_owner, COMSIG_XENOMORPH_ATTACK_LIVING)
+	return ..()
+
+/// Sets the chamber_scaling to the amount of active veil chambers.
+/datum/status_effect/mutation_upgrade/toxin/proc/update_buff()
+	SIGNAL_HANDLER
+	update_chamber_scaling()
+
+/// Injects the human target with a variable amount of the selected reagent.
+/datum/status_effect/mutation_upgrade/toxin/proc/on_slash(datum/source, mob/living/target)
+	SIGNAL_HANDLER
+	if(!chamber_scaling || target.stat == DEAD || !ishuman(target) || !target.can_sting())
+		return
+	var/datum/reagent/glob_reagent = GLOB.chemical_reagents_list[selected_reagent]
+	if(!glob_reagent)
+		return
+	var/mob/living/carbon/human/human_target = target
+	human_target.reagents.add_reagent(selected_reagent, glob_reagent.custom_metabolism * chamber_scaling)
+
+// ***************************************
+// ***************************************
+// ***************************************
+/atom/movable/screen/alert/status_effect/pheromones
+	name = "Pheromones"
+	desc = "Allows to emit pheromones. Click to change pheromones."
+	icon_state = "xenobuff_phero"
+
+/atom/movable/screen/alert/status_effect/pheromones/Click()
+	var/datum/status_effect/mutation_upgrade/pheromones/status_effect = attached_effect
+	var/phero_choice = show_radial_menu(status_effect.buff_owner, status_effect.buff_owner, GLOB.pheromone_images_list, radius = 35, require_near = TRUE)
+	if(!phero_choice)
+		return
+	QDEL_NULL(status_effect.current_aura)
+	status_effect.emitted_aura = phero_choice
+	status_effect.create_aura()
+
+/datum/status_effect/mutation_upgrade/pheromones
+	id = "mutation_upgrade_pheromones"
+	alert_type = /atom/movable/screen/alert/status_effect/pheromones
+	chamber_structure = MUTATION_STRUCTURE_VEIL
+	/// The aura.
+	var/datum/aura_bearer/current_aura
+	/// The aura to emit.
+	var/emitted_aura = AURA_XENO_RECOVERY
+	/// The initial value of the aura's power.
+	var/aura_power_base = 1
+	/// The phero power to increase by.
+	var/aura_power_per_chamber = 1
+
+/datum/status_effect/mutation_upgrade/pheromones/on_apply()
+	if(!..())
+		return FALSE
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_UTILITY, PROC_REF(update_buff))
+	create_aura()
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/pheromones/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_UTILITY)
+	if(current_aura)
+		current_aura.stop_emitting()
+	return ..()
+
+/// (Re)creates the aura.
+/datum/status_effect/mutation_upgrade/pheromones/proc/create_aura()
+	if(current_aura)
+		QDEL_NULL(current_aura)
+	if(chamber_scaling)
+		current_aura = SSaura.add_emitter(buff_owner, emitted_aura, 6 + aura_power_per_chamber * chamber_scaling * 2, aura_power_base + aura_power_per_chamber * chamber_scaling, -1, FACTION_XENO, buff_owner.hivenumber)
+
+/// Sets the chamber_scaling to the amount of active veil chambers and recreates the aura.
+/datum/status_effect/mutation_upgrade/pheromones/proc/update_buff()
+	SIGNAL_HANDLER
+	update_chamber_scaling()
+	create_aura()
+
+// ***************************************
+// ***************************************
+// ***************************************
+/atom/movable/screen/alert/status_effect/trail
+	name = "Trail"
+	desc = "We leave a trail behind. Click to change trail."
+	icon_state = "xenobuff_generic"
+
+/atom/movable/screen/alert/status_effect/trail/Click()
+	var/datum/status_effect/mutation_upgrade/trail/effect = attached_effect
+	if(effect.buff_owner.incapacitated())
+		to_chat(usr, span_warning("Cant do that right now!"))
+		return
+	var/i = effect.selectable_trails.Find(effect.selected_trail)
+	if(length(effect.selectable_trails) == i)
+		effect.selected_trail = effect.selectable_trails[1]
+	else
+		effect.selected_trail = effect.selectable_trails[i+1]
+	effect.buff_owner.balloon_alert(effect.buff_owner, "[effect.selected_trail.name]")
+
+/datum/status_effect/mutation_upgrade/trail
+	id = "mutation_upgrade_trail"
+	alert_type = /atom/movable/screen/alert/status_effect/trail
+	chamber_structure = MUTATION_STRUCTURE_VEIL
+	/// The initial odds of the trail spawning.
+	var/base_chance = 25
+	/// The additional chance of the trail starting.
+	var/chance_per_chamber = 25
+	/// The selected trail that will spawn upon moving.
+	var/obj/selected_trail = /obj/effect/xenomorph/spray
+	/// A list of trails that can be selected
+	var/list/selectable_trails = list(
+		/obj/effect/xenomorph/spray,
+		/obj/alien/resin/sticky/thin/temporary
+	)
+
+/datum/status_effect/mutation_upgrade/trail/on_apply()
+	if(!..())
+		return FALSE
+	RegisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_UTILITY, PROC_REF(update_buff))
+	RegisterSignal(buff_owner, COMSIG_MOVABLE_MOVED, PROC_REF(create_trail))
+	return TRUE
+
+/datum/status_effect/mutation_upgrade/trail/on_remove()
+	UnregisterSignal(SSdcs, COMSIG_UPGRADE_CHAMBER_UTILITY)
+	UnregisterSignal(buff_owner, COMSIG_MOVABLE_MOVED)
+	return ..()
+
+/// Sets the chamber_scaling to the amount of active veil chambers.
+/datum/status_effect/mutation_upgrade/trail/proc/update_buff()
+	SIGNAL_HANDLER
+	update_chamber_scaling()
+
+/// Rolls the dice and creates the selected trail if the dice is right.
+/datum/status_effect/mutation_upgrade/trail/proc/create_trail()
+	SIGNAL_HANDLER
+	if(buff_owner.incapacitated() || buff_owner.lying_angle || buff_owner.resting || !chamber_scaling)
+		return
+	if(prob(base_chance + (chance_per_chamber * chamber_scaling)))
+		var/turf/T = get_turf(buff_owner)
+		if(T.density || isspaceturf(T))
+			return
+		for(var/obj/O in T.contents)
+			if(is_type_in_typecache(O, GLOB.no_sticky_resin))
+				return
+		if(selected_trail == /obj/effect/xenomorph/spray)
+			new selected_trail(T, rand(2 SECONDS, 5 SECONDS))
+			for(var/obj/O in T)
+				O.acid_spray_act(buff_owner)
+		else
+			new selected_trail(T)
diff --git a/code/game/objects/items/cocoon.dm b/code/game/objects/items/cocoon.dm
index 1073e7361a96c..4246dda1c0e7c 100644
--- a/code/game/objects/items/cocoon.dm
+++ b/code/game/objects/items/cocoon.dm
@@ -47,6 +47,14 @@
 	//Gives marine cloneloss for a total of 30.
 	victim.adjustCloneLoss(0.5)
 
+	// Slowly give biomass over time up to 9 biomass (assuming the time based on comment above is correct).
+	for(var/mob/living/carbon/xenomorph/xeno in GLOB.alive_xeno_list)
+		if(xeno.hivenumber != hivenumber)
+			continue
+		if(xeno.xeno_caste.caste_flags & CASTE_NO_BIOMASS)
+			continue
+		xeno.gain_biomass(0.1)
+
 /obj/structure/cocoon/take_damage(damage_amount, damage_type = BRUTE, armor_type = null, effects = TRUE, attack_dir, armour_penetration = 0, mob/living/blame_mob)
 	. = ..()
 	if(anchored && obj_integrity < max_integrity / 2)
@@ -71,6 +79,14 @@
 		var/datum/hive_status/hive_status = GLOB.hive_datums[hivenumber]
 		hive_status.update_tier_limits()
 		GLOB.round_statistics.larva_from_cocoon += larva_point_reward / xeno_job.job_points_needed
+		// 3.5 biomass to all xenomorphs.
+		for(var/mob/living/carbon/xenomorph/xeno in GLOB.alive_xeno_list)
+			if(xeno.hivenumber != hivenumber)
+				continue
+			if(xeno.xeno_caste.caste_flags & CASTE_NO_BIOMASS)
+				continue
+			xeno.gain_biomass(4)
+
 		release_victim()
 	update_icon()
 
diff --git a/code/game/objects/structures/xeno.dm b/code/game/objects/structures/xeno.dm
index 1d6f768981852..7a582b6a70fda 100644
--- a/code/game/objects/structures/xeno.dm
+++ b/code/game/objects/structures/xeno.dm
@@ -145,6 +145,10 @@
 	ignore_weed_destruction = FALSE
 	refundable = FALSE
 
+/obj/alien/resin/sticky/thin/temporary/Initialize(mapload)
+	. = ..()
+	addtimer(CALLBACK(src, PROC_REF(obj_destruction), MELEE), 3 SECONDS)
+
 //Resin Doors
 /obj/structure/mineral_door/resin
 	name = RESIN_DOOR
diff --git a/code/modules/mob/dead/observer/observer.dm b/code/modules/mob/dead/observer/observer.dm
index 10c85e8c91ba9..a07f2a37e304e 100644
--- a/code/modules/mob/dead/observer/observer.dm
+++ b/code/modules/mob/dead/observer/observer.dm
@@ -902,6 +902,7 @@ GLOBAL_VAR_INIT(observer_default_invisibility, INVISIBILITY_OBSERVER)
 		log_game("[key_name(usr)] has joined Valhalla as a Xenomorph.")
 		var/mob/living/carbon/xenomorph/new_xeno = new xeno_choice(pick(GLOB.spawns_by_job[/datum/job/fallen/xenomorph]))
 		new_xeno.transfer_to_hive(XENO_HIVE_FALLEN)
+		new_xeno.gain_biomass(100) // So they can test it out here.
 		ADD_TRAIT(new_xeno, TRAIT_VALHALLA_XENO, VALHALLA_TRAIT)
 		var/datum/job/xallhala_job = SSjob.GetJobType(/datum/job/fallen/xenomorph)
 		new_xeno.apply_assigned_role_to_spawn(xallhala_job)
diff --git a/code/modules/mob/living/carbon/xenomorph/abilities.dm b/code/modules/mob/living/carbon/xenomorph/abilities.dm
index 51c774ef65351..f4e60943a99ee 100644
--- a/code/modules/mob/living/carbon/xenomorph/abilities.dm
+++ b/code/modules/mob/living/carbon/xenomorph/abilities.dm
@@ -1399,6 +1399,21 @@
 	victim.do_jitter_animation(2)
 	victim.adjustCloneLoss(20)
 
+	var/list/mob/living/carbon/xenomorph/nearby_friendly_xenos = list()
+	for(var/mob/living/carbon/xenomorph/nearby_xeno AS in cheap_get_xenos_near(X, 7))
+		// Intentionally includes the owner.
+		if(!X.issamexenohive(nearby_xeno))
+			continue
+		if(nearby_xeno.xeno_caste.caste_flags & CASTE_NO_BIOMASS)
+			continue
+		nearby_friendly_xenos += nearby_xeno
+
+	if(length(nearby_friendly_xenos))
+		// Split the reward amongst every xeno nearby, including themselves.
+		var/biomass_per_xeno = round(15/length(nearby_friendly_xenos), 0.1)
+		for(var/mob/living/carbon/xenomorph/nearby_friendly_xeno AS in nearby_friendly_xenos)
+			nearby_friendly_xeno.gain_biomass(biomass_per_xeno)
+
 	ADD_TRAIT(victim, TRAIT_PSY_DRAINED, TRAIT_PSY_DRAINED)
 	if(HAS_TRAIT(victim, TRAIT_UNDEFIBBABLE))
 		victim.med_hud_set_status()
@@ -1509,6 +1524,7 @@
 	victim.dead_ticks = 0
 	ADD_TRAIT(victim, TRAIT_STASIS, TRAIT_STASIS)
 	X.eject_victim(TRUE, starting_turf)
+
 	if(owner.client)
 		var/datum/personal_statistics/personal_statistics = GLOB.personal_statistics_list[owner.ckey]
 		personal_statistics.cocooned++
diff --git a/code/modules/mob/living/carbon/xenomorph/castes/baneling/castedatum_baneling.dm b/code/modules/mob/living/carbon/xenomorph/castes/baneling/castedatum_baneling.dm
index 705d0a4fc4850..6791f5c3ebc2c 100644
--- a/code/modules/mob/living/carbon/xenomorph/castes/baneling/castedatum_baneling.dm
+++ b/code/modules/mob/living/carbon/xenomorph/castes/baneling/castedatum_baneling.dm
@@ -24,7 +24,7 @@
 	max_health = 100
 
 	// *** Flags *** //
-	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION
+	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION|CASTE_NO_BIOMASS
 	can_flags = CASTE_CAN_BE_QUEEN_HEALED
 	caste_traits = null
 
diff --git a/code/modules/mob/living/carbon/xenomorph/castes/beetle/castedatum_beetle.dm b/code/modules/mob/living/carbon/xenomorph/castes/beetle/castedatum_beetle.dm
index 94dc092dc0630..7e2524b3cdb30 100644
--- a/code/modules/mob/living/carbon/xenomorph/castes/beetle/castedatum_beetle.dm
+++ b/code/modules/mob/living/carbon/xenomorph/castes/beetle/castedatum_beetle.dm
@@ -24,7 +24,7 @@
 	max_health = 260
 
 	// *** Flags *** //
-	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION
+	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION|CASTE_NO_BIOMASS
 	can_flags = CASTE_CAN_BE_QUEEN_HEALED|CASTE_CAN_RIDE_CRUSHER
 	caste_traits = null
 
diff --git a/code/modules/mob/living/carbon/xenomorph/castes/hivemind/castedatum_hivemind.dm b/code/modules/mob/living/carbon/xenomorph/castes/hivemind/castedatum_hivemind.dm
index 32fff1412c34f..0bfe11a00de6c 100644
--- a/code/modules/mob/living/carbon/xenomorph/castes/hivemind/castedatum_hivemind.dm
+++ b/code/modules/mob/living/carbon/xenomorph/castes/hivemind/castedatum_hivemind.dm
@@ -22,7 +22,7 @@
 
 	maximum_active_caste = 1
 	// *** Flags *** //
-	caste_flags = CASTE_INNATE_PLASMA_REGEN|CASTE_FIRE_IMMUNE|CASTE_IS_BUILDER|CASTE_DO_NOT_ALERT_LOW_LIFE
+	caste_flags = CASTE_INNATE_PLASMA_REGEN|CASTE_FIRE_IMMUNE|CASTE_IS_BUILDER|CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_NO_BIOMASS
 	can_flags = CASTE_CAN_BE_QUEEN_HEALED|CASTE_CAN_BE_GIVEN_PLASMA
 	caste_traits = null
 
diff --git a/code/modules/mob/living/carbon/xenomorph/castes/mantis/castedatum_mantis.dm b/code/modules/mob/living/carbon/xenomorph/castes/mantis/castedatum_mantis.dm
index 190fa40955b4b..bff0c53574e43 100644
--- a/code/modules/mob/living/carbon/xenomorph/castes/mantis/castedatum_mantis.dm
+++ b/code/modules/mob/living/carbon/xenomorph/castes/mantis/castedatum_mantis.dm
@@ -25,7 +25,7 @@
 	max_health = 150
 
 	// *** Flags *** //
-	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION
+	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION|CASTE_NO_BIOMASS
 	can_flags = CASTE_CAN_BE_QUEEN_HEALED|CASTE_CAN_BE_GIVEN_PLASMA|CASTE_CAN_RIDE_CRUSHER
 	caste_traits = null
 
diff --git a/code/modules/mob/living/carbon/xenomorph/castes/nymph/castedatum_nymph.dm b/code/modules/mob/living/carbon/xenomorph/castes/nymph/castedatum_nymph.dm
index ad381f39c107f..de97402bcd3a8 100644
--- a/code/modules/mob/living/carbon/xenomorph/castes/nymph/castedatum_nymph.dm
+++ b/code/modules/mob/living/carbon/xenomorph/castes/nymph/castedatum_nymph.dm
@@ -24,7 +24,7 @@
 	max_health = 120
 
 	// *** Flags *** //
-	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION|CASTE_IS_BUILDER
+	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION|CASTE_IS_BUILDER|CASTE_NO_BIOMASS
 	can_flags = CASTE_CAN_BE_QUEEN_HEALED|CASTE_CAN_BE_GIVEN_PLASMA
 
 	// *** Defense *** //
diff --git a/code/modules/mob/living/carbon/xenomorph/castes/puppet/castedatum_puppet.dm b/code/modules/mob/living/carbon/xenomorph/castes/puppet/castedatum_puppet.dm
index 6840b7fb279cd..afa3aace7a811 100644
--- a/code/modules/mob/living/carbon/xenomorph/castes/puppet/castedatum_puppet.dm
+++ b/code/modules/mob/living/carbon/xenomorph/castes/puppet/castedatum_puppet.dm
@@ -15,7 +15,7 @@
 	plasma_max = 2
 	plasma_gain = 0
 	max_health = 250
-	caste_flags = CASTE_NOT_IN_BIOSCAN|CASTE_DO_NOT_ANNOUNCE_DEATH|CASTE_DO_NOT_ALERT_LOW_LIFE
+	caste_flags = CASTE_NOT_IN_BIOSCAN|CASTE_DO_NOT_ANNOUNCE_DEATH|CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_NO_BIOMASS
 	minimap_icon = "puppet"
 	soft_armor = list(MELEE = 14, BULLET = 3, LASER = 5, ENERGY = 3, BOMB = 0, BIO = 0, FIRE = 0, ACID = 0)
 
diff --git a/code/modules/mob/living/carbon/xenomorph/castes/scorpion/castedatum_scorpion.dm b/code/modules/mob/living/carbon/xenomorph/castes/scorpion/castedatum_scorpion.dm
index 42102310c5e56..66ef28d226b42 100644
--- a/code/modules/mob/living/carbon/xenomorph/castes/scorpion/castedatum_scorpion.dm
+++ b/code/modules/mob/living/carbon/xenomorph/castes/scorpion/castedatum_scorpion.dm
@@ -24,7 +24,7 @@
 	max_health = 130
 
 	// *** Flags *** //
-	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION
+	caste_flags = CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_A_MINION|CASTE_NO_BIOMASS
 	can_flags = CASTE_CAN_BE_QUEEN_HEALED|CASTE_CAN_BE_GIVEN_PLASMA|CASTE_CAN_RIDE_CRUSHER
 	caste_traits = null
 
diff --git a/code/modules/mob/living/carbon/xenomorph/castes/spiderling/castedatum_spiderling.dm b/code/modules/mob/living/carbon/xenomorph/castes/spiderling/castedatum_spiderling.dm
index 45a9b323f78d3..fb786ef7ebe0c 100644
--- a/code/modules/mob/living/carbon/xenomorph/castes/spiderling/castedatum_spiderling.dm
+++ b/code/modules/mob/living/carbon/xenomorph/castes/spiderling/castedatum_spiderling.dm
@@ -25,7 +25,7 @@
 	max_health = 125
 
 	// *** Flags *** //
-	caste_flags = CASTE_NOT_IN_BIOSCAN|CASTE_DO_NOT_ANNOUNCE_DEATH|CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_BUILDER
+	caste_flags = CASTE_NOT_IN_BIOSCAN|CASTE_DO_NOT_ANNOUNCE_DEATH|CASTE_DO_NOT_ALERT_LOW_LIFE|CASTE_IS_BUILDER|CASTE_NO_BIOMASS
 
 	// *** Minimap Icon *** //
 	minimap_icon = "spiderling"
diff --git a/code/modules/mob/living/carbon/xenomorph/evolution.dm b/code/modules/mob/living/carbon/xenomorph/evolution.dm
index 6cfccda4b9fb6..06b4f9a38a7af 100644
--- a/code/modules/mob/living/carbon/xenomorph/evolution.dm
+++ b/code/modules/mob/living/carbon/xenomorph/evolution.dm
@@ -173,6 +173,9 @@
 	new_xeno.hive?.update_ruler() // Since ruler wasn't set during initialization, update ruler now.
 	transfer_observers_to(new_xeno)
 
+	// Carry over the biomass
+	new_xeno.biomass = biomass
+
 	if(new_xeno.health - getBruteLoss(src) - getFireLoss(src) > 0) //Cmon, don't kill the new one! Shouldnt be possible though
 		new_xeno.bruteloss = bruteloss //Transfers the damage over.
 		new_xeno.fireloss = fireloss //Transfers the damage over.
diff --git a/code/modules/mob/living/carbon/xenomorph/hive_datum.dm b/code/modules/mob/living/carbon/xenomorph/hive_datum.dm
index 2accf2293d193..febaf5a85c8c0 100644
--- a/code/modules/mob/living/carbon/xenomorph/hive_datum.dm
+++ b/code/modules/mob/living/carbon/xenomorph/hive_datum.dm
@@ -24,6 +24,13 @@
 	var/list/obj/structure/xeno/pherotower/pherotowers = list()
 	///list of hivemind cores
 	var/list/obj/structure/xeno/hivemindcore/hivemindcores = list()
+	/// List of shell upgrade chambers.
+	var/list/obj/structure/xeno/upgrade_chamber/shell/shell_chambers = list()
+	/// List of spur upgrade chambers.
+	var/list/obj/structure/xeno/upgrade_chamber/spur/spur_chambers = list()
+	/// List of veil upgrade chambers.
+	var/list/obj/structure/xeno/upgrade_chamber/veil/veil_chambers = list()
+
 	var/tier3_xeno_limit
 	var/tier2_xeno_limit
 	/// Queue of all clients wanting to join xeno side
@@ -122,6 +129,13 @@
 	// Pheromone towers
 	for(var/obj/structure/xeno/pherotower/tower AS in GLOB.hive_datums[hivenumber].pherotowers)
 		.["hive_structures"] += list(get_structure_packet(tower))
+	// Upgrade chambers
+	for(var/obj/structure/xeno/upgrade_chamber/shell/chamber AS in GLOB.hive_datums[hivenumber].shell_chambers)
+		.["hive_structures"] += list(get_structure_packet(chamber))
+	for(var/obj/structure/xeno/upgrade_chamber/spur/chamber AS in GLOB.hive_datums[hivenumber].spur_chambers)
+		.["hive_structures"] += list(get_structure_packet(chamber))
+	for(var/obj/structure/xeno/upgrade_chamber/veil/chamber AS in GLOB.hive_datums[hivenumber].veil_chambers)
+		.["hive_structures"] += list(get_structure_packet(chamber))
 	// Hivemind cores
 	for(var/obj/structure/xeno/hivemindcore/core AS in GLOB.hive_datums[hivenumber].hivemindcores)
 		.["hive_structures"] += list(get_structure_packet(core))
@@ -262,6 +276,10 @@
 			if(!isxeno(usr))
 				return
 			SEND_SIGNAL(usr, COMSIG_XENOABILITY_BLESSINGSMENU)
+		if("Mutations")
+			if(!isxeno(usr))
+				return
+			GLOB.mutation_selector.interact(usr)
 		if("Compass")
 			var/atom/target = locate(params["target"])
 			if(isobserver(usr))
diff --git a/code/modules/mob/living/carbon/xenomorph/hive_upgrades.dm b/code/modules/mob/living/carbon/xenomorph/hive_upgrades.dm
index 0e7f79c9bf16f..285665df9b3e2 100644
--- a/code/modules/mob/living/carbon/xenomorph/hive_upgrades.dm
+++ b/code/modules/mob/living/carbon/xenomorph/hive_upgrades.dm
@@ -264,6 +264,51 @@ GLOBAL_LIST_INIT(tier_to_primo_upgrade, list(
 			to_chat(buyer, span_xenowarning("You cannot build in a dense location!"))
 		return FALSE
 
+/datum/hive_upgrade/building/upgrade_chamber
+	gamemode_flags = ABILITY_NUCLEARWAR
+	building_loc = 0
+	/// The maximum amount of buildings that can exist before being disallowed from buying more.
+	var/max_chambers = 3
+
+/datum/hive_upgrade/building/upgrade_chamber/shell
+	name = "Shell Upgrade Chamber"
+	desc = "Constructs a chamber that allows xenos to buy survival mutations. Build up to 3 structures to increase mutation power."
+	icon = "shell"
+	psypoint_cost = 300
+	building_type = /obj/structure/xeno/upgrade_chamber/shell
+
+/datum/hive_upgrade/building/upgrade_chamber/shell/can_buy(mob/living/carbon/xenomorph/buyer, silent = TRUE)
+	. = ..()
+	if(length(buyer.hive.shell_chambers) >= max_chambers)
+		to_chat(buyer, span_xenowarning("Hive cannot support more than [max_chambers] active shell chambers!"))
+		return FALSE
+
+/datum/hive_upgrade/building/upgrade_chamber/spur
+	name = "Spur Upgrade Chamber"
+	desc = "Constructs a chamber that allows xenos to buy attack mutations. Build up to 3 structures to increase mutation power."
+	icon = "spur"
+	psypoint_cost = 250
+	building_type = /obj/structure/xeno/upgrade_chamber/spur
+
+/datum/hive_upgrade/building/upgrade_chamber/spur/can_buy(mob/living/carbon/xenomorph/buyer, silent = TRUE)
+	. = ..()
+	if(length(buyer.hive.spur_chambers) >= max_chambers)
+		to_chat(buyer, span_xenowarning("Hive cannot support more than [max_chambers] active spur chambers!"))
+		return FALSE
+
+/datum/hive_upgrade/building/upgrade_chamber/veil
+	name = "Veil Upgrade Chamber"
+	desc = "Constructs a chamber that allows xenos to buy utility mutations. Build up to 3 structures to increase mutation power."
+	icon = "veil"
+	psypoint_cost = 200
+	building_type = /obj/structure/xeno/upgrade_chamber/veil
+
+/datum/hive_upgrade/building/upgrade_chamber/veil/can_buy(mob/living/carbon/xenomorph/buyer, silent = TRUE)
+	. = ..()
+	if(length(buyer.hive.veil_chambers) >= max_chambers)
+		to_chat(buyer, span_xenowarning("Hive cannot support more than [max_chambers] active veil chambers!"))
+		return FALSE
+
 /datum/hive_upgrade/defence
 	category = "Defences"
 
diff --git a/code/modules/mob/living/carbon/xenomorph/mutation_datum.dm b/code/modules/mob/living/carbon/xenomorph/mutation_datum.dm
new file mode 100644
index 0000000000000..9ce6dc58ad347
--- /dev/null
+++ b/code/modules/mob/living/carbon/xenomorph/mutation_datum.dm
@@ -0,0 +1,204 @@
+/datum/mutation_datum
+	interaction_flags = INTERACT_UI_INTERACT
+
+/datum/mutation_datum/ui_state(mob/user)
+	return GLOB.hive_ui_state // Similar purpose.
+
+/datum/mutation_datum/ui_interact(mob/user, datum/tgui/ui)
+	ui = SStgui.try_update_ui(user, src, ui)
+	if(!ui)
+		ui = new(user, src, "MutationSelector", "Mutation Selector")
+		ui.open()
+
+/datum/mutation_datum/ui_data(mob/living/carbon/xenomorph/xeno_user)
+	var/list/data = list()
+
+	data["shell_chambers"] = length(xeno_user.hive?.shell_chambers)
+	data["spur_chambers"] = length(xeno_user.hive?.spur_chambers)
+	data["veil_chambers"] = length(xeno_user.hive?.veil_chambers)
+	data["biomass"] = xeno_user.biomass
+	return data
+
+/datum/mutation_datum/ui_static_data(mob/living/carbon/xenomorph/xeno_user)
+	var/list/data = list()
+
+	// Cost is not expected to change as switching castes closes the UI.
+	switch(xeno_user.xeno_caste.tier)
+		if(XENO_TIER_ONE)
+			data["cost"] = XENO_UPGRADE_BIOMASS_COST_T1
+		if(XENO_TIER_TWO)
+			data["cost"] = XENO_UPGRADE_BIOMASS_COST_T2
+		if(XENO_TIER_THREE)
+			data["cost"] = XENO_UPGRADE_BIOMASS_COST_T3
+		else
+			data["cost"] = XENO_UPGRADE_BIOMASS_COST_T4
+
+	data["survival_mutations"] = list()
+	for(var/datum/mutation_upgrade/survival/subtype_survival_mutation AS in subtypesof(/datum/mutation_upgrade/survival))
+		data["survival_mutations"] += list(list( // Double listing is how it needs to work.
+			"name" = subtype_survival_mutation.name,
+			"desc" = subtype_survival_mutation.desc,
+			"owned" = locate(subtype_survival_mutation.status_effect) in xeno_user.status_effects
+		))
+
+	data["attack_mutations"] = list()
+	for(var/datum/mutation_upgrade/attack/subtype_attack_mutation AS in subtypesof(/datum/mutation_upgrade/attack))
+		data["attack_mutations"] += list(list(
+			"name" = subtype_attack_mutation.name,
+			"desc" = subtype_attack_mutation.desc,
+			"owned" = locate(subtype_attack_mutation.status_effect) in xeno_user.status_effects
+		))
+
+	data["utility_mutations"] = list()
+	for(var/datum/mutation_upgrade/utility/subtype_utility_mutation AS in subtypesof(/datum/mutation_upgrade/utility))
+		data["utility_mutations"] += list(list(
+			"name" = subtype_utility_mutation.name,
+			"desc" = subtype_utility_mutation.desc,
+			"owned" = locate(subtype_utility_mutation.status_effect) in xeno_user.status_effects
+		))
+
+	return data
+
+/datum/mutation_datum/ui_act(action, params)
+	. = ..()
+	if(.)
+		return
+	if(!isxeno(usr))
+		return
+
+	switch(action)
+		if("purchase")
+			try_purchase_mutation(usr, params["upgrade_name"])
+
+	SStgui.close_user_uis(usr, src)
+
+/// Tries to purchase a mutation. Denies if possible. Otherwise, removes conflicting mutations and gives the purchased mutation.
+/datum/mutation_datum/proc/try_purchase_mutation(mob/living/carbon/xenomorph/xeno_purchaser, upgrade_name)
+	if(!upgrade_name)
+		return
+
+	var/upgrade_price
+	switch(xeno_purchaser.xeno_caste.tier)
+		if(XENO_TIER_ONE)
+			upgrade_price = XENO_UPGRADE_BIOMASS_COST_T1
+		if(XENO_TIER_TWO)
+			upgrade_price = XENO_UPGRADE_BIOMASS_COST_T2
+		if(XENO_TIER_THREE)
+			upgrade_price = XENO_UPGRADE_BIOMASS_COST_T3
+		else
+			upgrade_price = XENO_UPGRADE_BIOMASS_COST_T4
+
+	if(xeno_purchaser.biomass < upgrade_price)
+		to_chat(usr, span_warning("You don't have enough biomass!"))
+		return
+
+	var/datum/mutation_upgrade/chosen_mutation_upgrade
+	for(var/datum/mutation_upgrade/subtype_mutation AS in GLOB.mutation_upgrades_buyable)
+		if(subtype_mutation.name == upgrade_name)
+			chosen_mutation_upgrade = subtype_mutation
+			break
+
+	if(!chosen_mutation_upgrade)
+		return
+
+	switch(chosen_mutation_upgrade.required_structure)
+		if(MUTATION_STRUCTURE_CHAMBER)
+			if(!length(xeno_purchaser.hive?.shell_chambers))
+				to_chat(usr, span_xenonotice("This mutation requires a shell chamber to exist!"))
+				return
+		if(MUTATION_STRUCTURE_SPUR)
+			if(!length(xeno_purchaser.hive?.spur_chambers))
+				to_chat(usr, span_xenonotice("This mutation requires a spur chamber to exist!"))
+				return
+		if(MUTATION_STRUCTURE_VEIL)
+			if(!length(xeno_purchaser.hive?.veil_chambers))
+				to_chat(usr, span_xenonotice("This mutation requires a veil chamber to exist!"))
+				return
+
+	var/existing_upgrade = locate(chosen_mutation_upgrade.status_effect) in xeno_purchaser.status_effects
+	if(existing_upgrade)
+		to_chat(usr, span_xenonotice("Existing mutation chosen. No biomass spent."))
+		return
+
+	var/list/mutation_status_effects_to_remove = list()
+	for(var/datum/mutation_upgrade/subtype_mutation AS in GLOB.mutation_upgrades_buyable)
+		if(chosen_mutation_upgrade.category == subtype_mutation.category)
+			mutation_status_effects_to_remove += subtype_mutation.status_effect
+
+	xeno_purchaser.use_biomass(upgrade_price)
+	to_chat(xeno_purchaser, span_xenonotice("Mutation gained."))
+	for(var/datum/status_effect/removed_status_effect AS in mutation_status_effects_to_remove)
+		xeno_purchaser.remove_status_effect(removed_status_effect)
+	xeno_purchaser.do_jitter_animation(500)
+	xeno_purchaser.apply_status_effect(chosen_mutation_upgrade.status_effect)
+
+/datum/mutation_upgrade
+	/// The name that is displayed in the TGUI.
+	var/name
+	/// The description that is displayed in the TGUI.
+	var/desc
+	/// The category slot that this upgrade takes. Upgrades that conflict with this category slot will be removed/replaced.
+	var/category
+	/// The structure that needs to exist for a successful purchase.
+	var/required_structure
+	/// The status effect given upon successful purchase.
+	var/datum/status_effect/status_effect
+
+/datum/mutation_upgrade/survival
+	category = MUTATION_CATEGORY_SURVIVAL
+	required_structure = MUTATION_STRUCTURE_CHAMBER
+
+/datum/mutation_upgrade/survival/carapace
+	name = "Carapace"
+	desc = "Increases our soft armor by 2.5 per Shell Chamber."
+	status_effect = STATUS_EFFECT_UPGRADE_CARAPACE
+
+/datum/mutation_upgrade/survival/regeneration
+	name = "Regeneration"
+	desc = "When regenerating health on weeds, regenerate 0.8% max health and 0.167 sunder per Shell Chamber."
+	status_effect = STATUS_EFFECT_UPGRADE_REGENERATION
+
+/datum/mutation_upgrade/survival/vampirism
+	name = "Vampirism"
+	desc = "When slashing living humans, heal 1.67% max health per Shell Chamber. Ravagers get half the bonus instead."
+	status_effect = STATUS_EFFECT_UPGRADE_VAMPIRISM
+
+/datum/mutation_upgrade/attack
+	category = MUTATION_CATEGORY_ATTACK
+	required_structure = MUTATION_STRUCTURE_SPUR
+
+/datum/mutation_upgrade/attack/celerity
+	name = "Celerity"
+	desc = "Move -0.1 units faster per Spur Chamber."
+	category = MUTATION_CATEGORY_ATTACK
+	required_structure = MUTATION_STRUCTURE_SPUR
+	status_effect = STATUS_EFFECT_UPGRADE_CELERITY
+
+/datum/mutation_upgrade/attack/adrenaline
+	name = "Adrenaline"
+	desc = "When regenerating plasma on weeds, regenerate 5% additional plasma and 1% maximum plasma per Spur Chamber. It is doubled if resting."
+	status_effect = STATUS_EFFECT_UPGRADE_ADRENALINE
+
+/datum/mutation_upgrade/attack/crush
+	name = "Crush"
+	desc = "When attacking structures, deal a second instance of damage that is a 1/3 of your melee damage with 15 AP per Spur Chamber."
+	status_effect = STATUS_EFFECT_UPGRADE_CRUSH
+
+/datum/mutation_upgrade/utility
+	category = MUTATION_CATEGORY_UTILITY
+	required_structure = MUTATION_STRUCTURE_VEIL
+
+/datum/mutation_upgrade/utility/toxin
+	name = "Toxin"
+	desc = "When slashing living humans, inject a variable amount of a chosen toxin into them. The amount depends on the toxin and Spur Chamber count."
+	status_effect = STATUS_EFFECT_UPGRADE_TOXIN
+
+/datum/mutation_upgrade/utility/pheromones
+	name = "Pheromones"
+	desc = "Allows you to emit a chosen pheromone starting at a power of 1 and an additional 1 per Veil Chamber."
+	status_effect = STATUS_EFFECT_UPGRADE_PHERO
+
+/datum/mutation_upgrade/utility/trail
+	name = "Trail"
+	desc = "When moving, randomly leave a chosen trail underneath you at a 25% chance and an additional 25% per Veil Chamber."
+	status_effect = STATUS_EFFECT_UPGRADE_TRAIL
diff --git a/code/modules/mob/living/carbon/xenomorph/xeno_defines.dm b/code/modules/mob/living/carbon/xenomorph/xeno_defines.dm
index 624a032f869d3..03f81d4326ae8 100644
--- a/code/modules/mob/living/carbon/xenomorph/xeno_defines.dm
+++ b/code/modules/mob/living/carbon/xenomorph/xeno_defines.dm
@@ -347,6 +347,8 @@ GLOBAL_LIST_INIT(strain_list, init_glob_strain_list())
 	///Will increase by 10 every decisecond if under 0.
 	///Increases by xeno_caste.regen_ramp_amount every decisecond. If you want to balance this, look at the xeno_caste defines mentioned above.
 	var/regen_power = 0
+	/// The amount of biomass stored. Used for Chamber Upgrades.
+	var/biomass = 0
 
 	var/zoom_turf = null
 
diff --git a/code/modules/mob/living/carbon/xenomorph/xenoprocs.dm b/code/modules/mob/living/carbon/xenomorph/xenoprocs.dm
index a173fb124683d..557c99ecd5140 100644
--- a/code/modules/mob/living/carbon/xenomorph/xenoprocs.dm
+++ b/code/modules/mob/living/carbon/xenomorph/xenoprocs.dm
@@ -126,6 +126,10 @@
 	else //Upgrade process finished or impossible
 		. += "Upgrade Progress: (FINISHED)"
 
+	if(!(xeno_caste.caste_flags & CASTE_NO_BIOMASS))
+		. += "Biomass: [biomass]/100"
+
+
 	. += "Health: [health]/[maxHealth][overheal ? " + [overheal]": ""]" //Changes with balance scalar, can't just use the caste
 
 	if(xeno_caste.plasma_max > 0)
@@ -580,3 +584,9 @@
 
 /mob/living/carbon/xenomorph/on_eord(turf/destination)
 	revive(TRUE)
+
+/mob/living/carbon/xenomorph/proc/use_biomass(value)
+	biomass = clamp(biomass - value, 0, 100)
+
+/mob/living/carbon/xenomorph/proc/gain_biomass(value)
+	biomass = clamp(biomass + value, 0, 100)
diff --git a/code/modules/xenomorph/upgrade_chambers.dm b/code/modules/xenomorph/upgrade_chambers.dm
new file mode 100644
index 0000000000000..719d05adb0a09
--- /dev/null
+++ b/code/modules/xenomorph/upgrade_chambers.dm
@@ -0,0 +1,62 @@
+/obj/structure/xeno/upgrade_chamber
+	name = "upgrade chamber"
+	desc = "You shouldn't see this!"
+	icon = 'icons/Xeno/1x1building.dmi'
+	icon_state = "shell_chamber"
+	bound_width = 32
+	bound_height = 32
+	max_integrity = 500
+	resistance_flags = UNACIDABLE | DROPSHIP_IMMUNE
+	xeno_structure_flags = IGNORE_WEED_REMOVAL | CRITICAL_STRUCTURE
+
+/obj/structure/xeno/upgrade_chamber/Initialize(mapload, _hivenumber)
+	. = ..()
+	SSminimaps.add_marker(src, MINIMAP_FLAG_XENO, image('icons/UI_icons/map_blips.dmi', null, "upgrade_chamber", ABOVE_FLOAT_LAYER))
+
+/obj/structure/xeno/upgrade_chamber/shell
+	name = "Shell Chamber"
+	desc = "Shell upgrade chamber"
+	icon_state = "shell_chamber"
+
+/obj/structure/xeno/upgrade_chamber/shell/Initialize(mapload, _hivenumber)
+	. = ..()
+	set_light(3, 1, COLOR_DARK_CYAN)
+	GLOB.hive_datums[hivenumber].shell_chambers += src
+	SEND_GLOBAL_SIGNAL(COMSIG_UPGRADE_CHAMBER_SURVIVAL)
+
+/obj/structure/xeno/upgrade_chamber/shell/Destroy()
+	GLOB.hive_datums[hivenumber].shell_chambers -= src
+	SEND_GLOBAL_SIGNAL(COMSIG_UPGRADE_CHAMBER_SURVIVAL)
+	return ..()
+
+/obj/structure/xeno/upgrade_chamber/spur
+	name = "Spur Chamber"
+	desc = "Spur upgrade chamber"
+	icon_state = "spur_chamber"
+
+/obj/structure/xeno/upgrade_chamber/spur/Initialize(mapload, _hivenumber)
+	. = ..()
+	set_light(3, 1, COLOR_RED)
+	GLOB.hive_datums[hivenumber].spur_chambers += src
+	SEND_GLOBAL_SIGNAL(COMSIG_UPGRADE_CHAMBER_ATTACK)
+
+/obj/structure/xeno/upgrade_chamber/spur/Destroy()
+	GLOB.hive_datums[hivenumber].spur_chambers -= src
+	SEND_GLOBAL_SIGNAL(COMSIG_UPGRADE_CHAMBER_ATTACK)
+	return ..()
+
+/obj/structure/xeno/upgrade_chamber/veil
+	name = "Veil Chamber"
+	desc = "Veil upgrade chamber"
+	icon_state = "veil_chamber"
+
+/obj/structure/xeno/upgrade_chamber/veil/Initialize(mapload, _hivenumber)
+	. = ..()
+	set_light(3, 1, COLOR_LIME)
+	GLOB.hive_datums[hivenumber].veil_chambers += src
+	SEND_GLOBAL_SIGNAL(COMSIG_UPGRADE_CHAMBER_UTILITY)
+
+/obj/structure/xeno/upgrade_chamber/veil/Destroy()
+	GLOB.hive_datums[hivenumber].veil_chambers -= src
+	SEND_GLOBAL_SIGNAL(COMSIG_UPGRADE_CHAMBER_UTILITY)
+	return ..()
diff --git a/icons/UI_Icons/buyable_icons.dmi b/icons/UI_Icons/buyable_icons.dmi
index 44bdaec35b984..e1ce480200489 100644
Binary files a/icons/UI_Icons/buyable_icons.dmi and b/icons/UI_Icons/buyable_icons.dmi differ
diff --git a/icons/UI_Icons/map_blips.dmi b/icons/UI_Icons/map_blips.dmi
index b38bbe215fb77..fa6c1cd80f6e3 100644
Binary files a/icons/UI_Icons/map_blips.dmi and b/icons/UI_Icons/map_blips.dmi differ
diff --git a/icons/Xeno/1x1building.dmi b/icons/Xeno/1x1building.dmi
index b58708b539aa3..d4ac402de1aaf 100644
Binary files a/icons/Xeno/1x1building.dmi and b/icons/Xeno/1x1building.dmi differ
diff --git a/icons/mob/screen_alert.dmi b/icons/mob/screen_alert.dmi
index ad6e246e92201..af132dd3a6ac6 100644
Binary files a/icons/mob/screen_alert.dmi and b/icons/mob/screen_alert.dmi differ
diff --git a/tgmc.dme b/tgmc.dme
index 51ac661d0895c..11581277b6023 100644
--- a/tgmc.dme
+++ b/tgmc.dme
@@ -1786,6 +1786,7 @@ F// DM Environment file for baystation12.dme.
 #include "code\modules\mob\living\carbon\xenomorph\hive_upgrades.dm"
 #include "code\modules\mob\living\carbon\xenomorph\life.dm"
 #include "code\modules\mob\living\carbon\xenomorph\login.dm"
+#include "code\modules\mob\living\carbon\xenomorph\mutation_datum.dm"
 #include "code\modules\mob\living\carbon\xenomorph\saddles.dm"
 #include "code\modules\mob\living\carbon\xenomorph\say.dm"
 #include "code\modules\mob\living\carbon\xenomorph\update_icons.dm"
@@ -2280,6 +2281,7 @@ F// DM Environment file for baystation12.dme.
 #include "code\modules\xenomorph\spawner.dm"
 #include "code\modules\xenomorph\trap.dm"
 #include "code\modules\xenomorph\tunnel.dm"
+#include "code\modules\xenomorph\upgrade_chambers.dm"
 #include "code\modules\xenomorph\xeno_turret.dm"
 #include "code\modules\xenomorph\xenoplant.dm"
 #include "code\modules\xenomorph\xenotowers.dm"
diff --git a/tgui/packages/tgui/interfaces/HiveStatus.tsx b/tgui/packages/tgui/interfaces/HiveStatus.tsx
index 5f89779d85c8e..75a7417765881 100644
--- a/tgui/packages/tgui/interfaces/HiveStatus.tsx
+++ b/tgui/packages/tgui/interfaces/HiveStatus.tsx
@@ -190,15 +190,12 @@ const BlessingsButton = (_props: any) => {
   const { act, data } = useBackend<InputPack>();
   const { user_purchase_perms, user_ref } = data;
 
-  if (!user_purchase_perms) {
-    return <Box />;
-  }
-
   return (
     <Box className="Section__buttons">
       <Button
         onClick={() => act('Blessings', { xeno: user_ref })}
         icon={'store'}
+        disabled={!user_purchase_perms}
       >
         Blessings
       </Button>
@@ -206,6 +203,22 @@ const BlessingsButton = (_props: any) => {
   );
 };
 
+const MutationsButton = (_props: any) => {
+  const { act, data } = useBackend<InputPack>();
+  const { user_ref } = data;
+
+  return (
+    <Box className="Section__buttons" mr="90px">
+      <Button
+        onClick={() => act('Mutations', { xeno: user_ref })}
+        icon={'store'}
+      >
+        Mutations
+      </Button>
+    </Box>
+  );
+};
+
 const GeneralInfo = (_props: any) => {
   const { data } = useBackend<InputPack>();
   const {
@@ -253,7 +266,10 @@ const GeneralInfo = (_props: any) => {
             {' ' + hive_larva_burrowed}
           </Box>
         </Box>
-        <BlessingsButton />
+        <Box as="span">
+          <MutationsButton />
+          <BlessingsButton />
+        </Box>
       </Box>
       <Flex direction="column" className="Section__content">
         <Flex.Item>
diff --git a/tgui/packages/tgui/interfaces/MutationSelector.tsx b/tgui/packages/tgui/interfaces/MutationSelector.tsx
new file mode 100644
index 0000000000000..2dbc586dc4892
--- /dev/null
+++ b/tgui/packages/tgui/interfaces/MutationSelector.tsx
@@ -0,0 +1,168 @@
+import { useBackend } from '../backend';
+import {
+  Button,
+  Collapsible,
+  Flex,
+  ProgressBar,
+  Section,
+  Tooltip,
+} from '../components';
+import { Window } from '../layouts';
+
+type Upgrade = {
+  name: string;
+  desc: string;
+  owned: boolean;
+};
+
+type BiomassData = {
+  biomass: number;
+  cost: number;
+};
+
+type SurvivalMutationData = {
+  survival_mutations: Upgrade[];
+  shell_chambers: number;
+  biomass: number;
+  cost: number;
+};
+
+type AttackMutationData = {
+  attack_mutations: Upgrade[];
+  spur_chambers: number;
+  biomass: number;
+  cost: number;
+};
+
+type UtilityMutationData = {
+  utility_mutations: Upgrade[];
+  veil_chambers: number;
+  biomass: number;
+  cost: number;
+};
+
+export const MutationSelector = (_props: any) => {
+  return (
+    <Window theme="xeno" width={500} height={600}>
+      <Window.Content scrollable>
+        <Section title="Biomass" key="Biomass">
+          <BiomassBar />
+        </Section>
+        <SurvivalMutationSection />
+        <AttackMutationSection />
+        <UtilityMutationSection />
+      </Window.Content>
+    </Window>
+  );
+};
+
+const BiomassBar = (_props: any) => {
+  const { data } = useBackend<BiomassData>();
+  const { biomass, cost } = data;
+
+  return (
+    <Tooltip content={`Costs ${cost} biomass to buy an upgrade!`}>
+      <Flex mb={1}>
+        <Flex.Item grow>
+          <ProgressBar color="green" value={biomass / 100}>
+            {`${biomass} / 100 `}
+          </ProgressBar>
+        </Flex.Item>
+      </Flex>
+    </Tooltip>
+  );
+};
+
+const SurvivalMutationSection = (_props: any) => {
+  const { act, data } = useBackend<SurvivalMutationData>();
+  const { survival_mutations, shell_chambers, cost, biomass } = data;
+
+  return (
+    <Collapsible
+      title={`Survival Mutations | Shell Chambers: ${shell_chambers}/3`}
+    >
+      {survival_mutations.map((mutation) => (
+        <Section
+          title={`${mutation.name}`}
+          mb={1}
+          key={mutation.name}
+          buttons={
+            <Button
+              content={`Buy (${cost})`}
+              key={mutation.name}
+              onClick={() => act('purchase', { upgrade_name: mutation.name })}
+              disabled={cost > biomass || shell_chambers === 0}
+              selected={mutation.owned}
+            />
+          }
+        >
+          <Flex direction="column-reverse" align={'left'}>
+            {mutation.desc}
+          </Flex>
+        </Section>
+      ))}
+    </Collapsible>
+  );
+};
+
+const AttackMutationSection = (_props: any) => {
+  const { act, data } = useBackend<AttackMutationData>();
+  const { attack_mutations, spur_chambers, cost, biomass } = data;
+
+  return (
+    <Collapsible title={`Attack Mutations | Spur Chambers: ${spur_chambers}/3`}>
+      {attack_mutations.map((mutation) => (
+        <Section
+          title={`${mutation.name}`}
+          mb={1}
+          key={mutation.name}
+          buttons={
+            <Button
+              content={`Buy (${cost})`}
+              key={mutation.name}
+              onClick={() => act('purchase', { upgrade_name: mutation.name })}
+              disabled={cost > biomass || spur_chambers === 0}
+              selected={mutation.owned}
+            />
+          }
+        >
+          <Flex direction="column-reverse" align={'left'}>
+            {mutation.desc}
+          </Flex>
+        </Section>
+      ))}
+    </Collapsible>
+  );
+};
+
+const UtilityMutationSection = (_props: any) => {
+  const { act, data } = useBackend<UtilityMutationData>();
+  const { utility_mutations, veil_chambers, cost, biomass } = data;
+
+  return (
+    <Collapsible
+      title={`Utility Mutations | Veil Chambers: ${veil_chambers}/3`}
+    >
+      {utility_mutations.map((mutation) => (
+        <Section
+          title={`${mutation.name}`}
+          mb={1}
+          key={mutation.name}
+          buttons={
+            <Button
+              content={`Buy (${cost})`}
+              key={mutation.name}
+              onClick={() => act('purchase', { upgrade_name: mutation.name })}
+              disabled={cost > biomass || veil_chambers === 0}
+              selected={mutation.owned}
+            />
+          }
+        >
+          <Flex direction="column-reverse" align={'left'}>
+            {mutation.desc}
+          </Flex>
+        </Section>
+      ))}
+    </Collapsible>
+  );
+};