Sewage Banshee Grendel
From Creatures Wikia
The Sewage Banshee Grendels are one of two Toxic Grendel breeds by Grendel Man. They are like Toxic Norns in the fact they can live in a toxic enviroment. But they cannot take any cures at all, only toxins. Medicine One, in particular, can quickly kill a sewage banshee. Also, they are amphibious, and cannot lay eggs above water (This doesn't actually work-I plan on making a new version sometime soon that fixes this problem-Grendel Man).