Lizard frills are hidden by HIDEHAIR rather than HIDEEARS / Lizard frills are masked like hair by hats (#95986)

code/modules/mob/living/carbon/carbon_update_icons.dm

@@ -545,7 +545,7 @@
 	for(var/datum/bodypart_overlay/overlay as anything in bodypart_overlays)
 		if(!overlay.can_draw_on_bodypart(src, owner, is_husked))
 			continue
-		. += overlay.generate_icon_cache()
+		. += overlay.generate_icon_cache(src)
 	if(ishuman(owner))
 		var/mob/living/carbon/human/human_owner = owner
 		. += "[human_owner.mob_height]"
@@ -574,7 +574,7 @@
 	for(var/datum/bodypart_overlay/overlay as anything in bodypart_overlays)
 		if(!overlay.can_draw_on_bodypart(src, owner, TRUE))
 			continue
-		. += overlay.generate_icon_cache()
+		. += overlay.generate_icon_cache(src)
 	if(ishuman(owner))
 		var/mob/living/carbon/human/human_owner = owner
 		. += "[human_owner.mob_height]"

code/modules/mob/living/carbon/inventory.dm

@@ -174,6 +174,7 @@
 	if(item.hair_mask)
 		LAZYADD(hair_masks, item.hair_mask)
 		update_hair()
+		update_body() // this is solely for lizard frills
 	add_item_coverage(item)
 
 /mob/living/carbon/has_unequipped(obj/item/item)
@@ -185,6 +186,7 @@
 	if(item.hair_mask)
 		LAZYREMOVE(hair_masks, item.hair_mask)
 		update_hair()
+		update_body() // this is solely for lizard frills
 	remove_item_coverage(item)
 
 /mob/living/carbon/doUnEquip(obj/item/item_dropping, force, newloc, no_move, invdrop = TRUE, silent = FALSE)

code/modules/surgery/organs/external/_visual_organs.dm

@@ -144,7 +144,32 @@ Unlike normal organs, we're actually inside a persons limbs at all times
 	feature_key = FEATURE_FRILLS
 
 /datum/bodypart_overlay/mutant/frills/can_draw_on_bodypart(obj/item/bodypart/bodypart_owner, mob/living/carbon/owner, is_husked = FALSE)
-	return ..() && !(bodypart_owner.owner?.obscured_slots & HIDEEARS)
+	return ..() && !(bodypart_owner.owner?.obscured_slots & HIDEHAIR)
+
+/datum/bodypart_overlay/mutant/frills/generate_icon_cache(obj/item/bodypart/limb)
+	. = ..()
+	if(LAZYLEN(limb?.owner?.hair_masks))
+		. += jointext(limb.owner.hair_masks, ",")
+
+/datum/bodypart_overlay/mutant/frills/get_image(image_layer, obj/item/bodypart/limb)
+	if(!LAZYLEN(limb?.owner?.hair_masks))
+		return ..()
+
+	var/list/hair_masks_to_use = limb.owner.hair_masks
+	var/icon_state_to_use = build_icon_state(image_layer, limb)
+	var/frill_cache_key = "[sprite_datum.type]-[icon_state_to_use]-[jointext(hair_masks_to_use, ",")]"
+	var/static/list/cached_frill_icons
+	var/icon/cached_icon = LAZYACCESS(cached_frill_icons, frill_cache_key)
+	if(isnull(cached_icon))
+		cached_icon = icon(sprite_datum.icon, build_icon_state(image_layer, limb))
+		for(var/datum/hair_mask/mask as anything in hair_masks_to_use)
+			cached_icon.Blend(icon(mask::icon, mask::icon_state), ICON_ADD)
+		LAZYSET(cached_frill_icons, frill_cache_key, cached_icon)
+
+	var/mutable_appearance/uncached_appearance = mutable_appearance(cached_icon, layer = image_layer)
+	if(sprite_datum.center)
+		center_image(uncached_appearance, sprite_datum.dimension_x, sprite_datum.dimension_y)
+	return uncached_appearance
 
 ///Guess what part of the lizard this is?
 /obj/item/organ/snout

code/modules/surgery/organs/external/wings/functional_wings.dm

@@ -183,7 +183,7 @@
 	feature_key = initial(feature_key)
 	set_appearance_from_name(sprite_datum.name)
 
-/datum/bodypart_overlay/mutant/wings/functional/generate_icon_cache()
+/datum/bodypart_overlay/mutant/wings/functional/generate_icon_cache(obj/item/bodypart/limb)
 	. = ..()
 	. += wings_open ? "open" : "closed"
 

code/modules/surgery/organs/internal/cyberimp/augments_internal.dm

@@ -56,7 +56,7 @@
 	implant = null
 	return ..()
 
-/datum/bodypart_overlay/augment/generate_icon_cache()
+/datum/bodypart_overlay/augment/generate_icon_cache(obj/item/bodypart/limb)
 	. = ..()
 	. += implant.get_overlay_state()