Spookyfish
Meanwhile, Cartman's double from another universe appears.  He is from an opposite universe where mean people are nice and nice people are mean, so this visiting Cartman is nice.  He helps the boys with their pumpkin carving contest.  He tries to help Stan and his friends defeat the evil fish.  All the characters from the evil universe have goatee beards, a reference to the "Mirror Mirror" episode of Star Trek.