the Indian Burial Ground Pet Store is a reference to this movie
Stan tells New Kid/Douchebag when going back to his room "Nice goldfish, I had one like that once, then it started killing people so we had to get rid of it." Cartman's evil goatee can be worn as an accessory.
Mrs. McCormrick coming into the Mash's house drunk after hearing about Kenny's death and what he used to do comes from this film spoofing a scene in which Mrs. Daigle does the same thing after her son was murdered.
Evil parallel universe, counterparts wear goatees