Cherrypicked xenophage-rewrite mechanics over.

code/datums/diseases/xeno_transformation.dm

@@ -53,9 +53,12 @@
 			affected_mob.updatehealth()
 			if(prob(40))
 				if(gibbed != 0) return 0
-				var/turf/T = find_loc(affected_mob)
-				gibs(T)
 				src.cure(0)
 				gibbed = 1
-				affected_mob:Alienize()
-
+				var/mob/living/carbon/human/H = affected_mob
+				if(istype(H))
+					var/turf/origin = find_loc(affected_mob)
+					gibs(origin)
+					H.set_species("Xenomorph [pick(list("Hunter","Sentinel","Drone"))]")
+					return
+				affected_mob.gib()