There are numerous references to H.P. Lovecraft and the Cthulhu Mythos, to the point of including Jeffrey Combs as "Professor Hatecraft". Combs has appeared in a number of films inspired by Lovecraft's fictions, and portrayed the man himself in one. The monster, Char-Gar Gothakon, resembles Cthulhu, a giant squid-faced monster in Lovecraft's stories. The episode's name, "The Shrieking Madness", is a reference to the fact that Cthulhu's shriek can cause madness and will bend the victims to Cthulhu's will.
Fred's father uses the expression "By Grabthar's Hammer!", a reference to the cult film Galaxy Quest (1999). In it, Alan Rickman's character uses the expression and has a makeup mold head that resembles a squid's tentacles near the back, somewhat resembling the Cthulhu-like nemesis of the gang has in the front.
Hatecraft's assistant/biggest fan is named Howard E. Robertson, a takeoff of Robert E. Howard, a fellow science fiction and fantasy writer, best known for Conan the Barbarian.
WILHELM SCREAM: By one of the Campus Burger waiters, who is picked up and thrown by Char-Gar Gothakon during the attack at Campus Burger.