Allows special Promethean NIF installation

Just shove it directly into their face. Make sure it's a bioadaptive one though otherwise it won't do anything.
Target head, click, wait a while. They ARE slime people or whatever so... makes sense :V

code/modules/nifsoft/nif.dm

@@ -572,3 +572,32 @@ You can also set the stat of a NIF to NIF_TEMPFAIL without any issues to disable
 	Will function in species where it normally wouldn't."
 	durability = 25
 	bioadap = TRUE
+
+////////////////////////////////
+// Special Promethean """surgery"""
+/obj/item/device/nif/attack(mob/living/M, mob/living/user, var/target_zone)
+	if(!ishuman(M) || !ishuman(user) || (M == user))
+		return ..()
+
+	var/mob/living/carbon/human/U = user
+	var/mob/living/carbon/human/T = M
+
+	if(istype(T.species,/datum/species/shapeshifter/promethean) && target_zone == BP_HEAD) //Are prommy, aimed at head.
+		if(T.head || T.glasses)
+			to_chat(user,"<span class='warning'>Remove any headgear they have on first, as it might interfere.</span>")
+			return
+		var/obj/item/organ/external/head = T.get_organ(BP_HEAD)
+		if(!T)
+			to_chat(user,"<span class='warning'>They should probably regrow their head first.</span>")
+			return
+		U.visible_message("<span class='notice'>[U] begins installing [src] into [T]'s head by just stuffing it in.</span>",
+		"<span class='notice'>You begin installing [src] into [T]'s head by just stuffing it in.</span>",
+		"There's a wet SQUISH noise.")
+		if(do_mob(user = user, target = T, time = 200, target_zone = BP_HEAD))
+			user.unEquip(src)
+			forceMove(head)
+			head.implants |= src
+			implant(T)
+			playsound(T,'sound/effects/slime_squish.ogg',50,1)
+	else
+		return ..()