When Stan ends up at PETA's compound for animals after being exiled from South Park for refusing to vote, he's given an ultimatum to join PETA or die. However, the main leader of the group says that Stan has to get permission from Dr. Cornwallis to stay there. As he goes into Dr. Cornwallis' tent, it turns out Dr. Cornwallis is actually a goat shown munching on hay. Stan just stands there speechless and knowing he's just an animal and therefore can't really talk doesn't even bother asking if he can stay. When Stan walks out of the tent, not wanting to die, he lies to all the other members saying that their leader said yes, to which all of PETA foolishly believe.
Later on, Dr. Cornwallis is seen munching on the brain of a dead PETA member after P. Diddy and his friends shoot up the compound.
Dr. Cornwallis takes the appearance of a usual goat, with white colored fur, brown horns, and crossed eyes.