Cory Walkers' backstory for Roarface is: That the metal collar around her neck prevents her from becoming ALL werewolf, so only her head is affected by her werewolf curse.
The book that Debbie finds in her closet is identical in appearance to the Necronomicon from 'The Evil Dead'.
Reginald VelJohnson, who Mark's high school is named after, plays the school's principal in this episode.
The title doesn't appear until over 15 minutes into the episode.
The odd effect of Machine Head's voice was done by running the voice actor's voice through auto-tune.