diff --git a/modular_nova/master_files/code/modules/client/preferences/mutant_parts.dm b/modular_nova/master_files/code/modules/client/preferences/mutant_parts.dm
index 5017204bbab..1fdec65c61e 100644
--- a/modular_nova/master_files/code/modules/client/preferences/mutant_parts.dm
+++ b/modular_nova/master_files/code/modules/client/preferences/mutant_parts.dm
@@ -8,17 +8,32 @@
 	default_value = FALSE
 
 /datum/preference/toggle/allow_mismatched_parts/apply_to_human(mob/living/carbon/human/target, value, datum/preferences/preferences)
-	return TRUE // we dont actually want this to do anything
+	return // we dont actually want this to do anything
 
 /datum/preference/toggle/allow_mismatched_parts/is_accessible(datum/preferences/preferences)
 	if(CONFIG_GET(flag/disable_mismatched_parts))
 		return FALSE
-	. = ..()
+	return ..()
 
-/datum/preference/toggle/allow_mismatched_parts/deserialize(input, datum/preferences/preferences)
+/datum/preference/toggle/allow_mismatched_parts/deserialize(input)
 	if(CONFIG_GET(flag/disable_mismatched_parts))
 		return FALSE
-	. = ..()
+	return ..()
+
+/datum/preference/toggle/allow_mismatched_hair_color
+	category = PREFERENCE_CATEGORY_SECONDARY_FEATURES
+	savefile_identifier = PREFERENCE_CHARACTER
+	savefile_key = "allow_mismatched_hair_color_toggle"
+	default_value = TRUE
+
+/datum/preference/toggle/allow_mismatched_hair_color/apply_to_human(mob/living/carbon/human/target, value, datum/preferences/preferences)
+	return // applied in apply_supplementary_body_changes()
+
+/datum/preference/toggle/allow_mismatched_hair_color/is_accessible(datum/preferences/preferences)
+	var/datum/species/species = preferences.read_preference(/datum/preference/choiced/species)
+	if(!ispath(species, /datum/species/jelly)) // only slimes can see this pref
+		return FALSE
+	return ..()
 
 /datum/preference/toggle/allow_emissives
 	category = PREFERENCE_CATEGORY_SECONDARY_FEATURES
diff --git a/modular_nova/modules/customization/modules/mob/living/carbon/human/species/roundstartslime.dm b/modular_nova/modules/customization/modules/mob/living/carbon/human/species/roundstartslime.dm
index 0877222dbdf..1e9b02d9722 100644
--- a/modular_nova/modules/customization/modules/mob/living/carbon/human/species/roundstartslime.dm
+++ b/modular_nova/modules/customization/modules/mob/living/carbon/human/species/roundstartslime.dm
@@ -57,6 +57,10 @@
 
 	return perk_descriptions
 
+/datum/species/jelly/roundstartslime/apply_supplementary_body_changes(mob/living/carbon/human/target, datum/preferences/preferences, visuals_only = FALSE)
+	if(preferences.read_preference(/datum/preference/toggle/allow_mismatched_hair_color))
+		target.dna.species.hair_color_mode = null
+
 /**
  * Alter Form is the ability of slimes to edit many of their character attributes at will
  * This covers most thing about their character, from body size or colour, to adding new wings, tails, ears, etc, to changing the presence of their genitalia
diff --git a/tgui/packages/tgui/interfaces/PreferencesMenu/preferences/features/character_preferences/nova/species_features.tsx b/tgui/packages/tgui/interfaces/PreferencesMenu/preferences/features/character_preferences/nova/species_features.tsx
index 6c89d1a9963..f13e41a36b0 100644
--- a/tgui/packages/tgui/interfaces/PreferencesMenu/preferences/features/character_preferences/nova/species_features.tsx
+++ b/tgui/packages/tgui/interfaces/PreferencesMenu/preferences/features/character_preferences/nova/species_features.tsx
@@ -116,6 +116,13 @@ export const allow_mismatched_parts_toggle: FeatureToggle = {
   component: CheckboxInput,
 };
 
+export const allow_mismatched_hair_color_toggle: FeatureToggle = {
+  name: 'Allow Mismatched Hair Color',
+  description:
+    'Allows species who normally have a fixed hair color to have different hair colors. This includes in-round sources such as dyeing hair, alter form, etc. Currently only applicable to slimes.',
+  component: CheckboxInput,
+};
+
 export const allow_genitals_toggle: FeatureToggle = {
   name: 'Allow Genital Parts',
   description: 'Enables if you want to have genitals on your character.',