Gary Frieling, the first victim whose heart burst through his chest, is named after Friz Freleng, who directed hundreds of Looney Tunes/Merry Melodies cartoons.
Maxine Miller portraying Sheila, a resident at the assisted living facility, has provided the voice for multiple characters in several animated feature movies and cartoon series.
There is a character closely related to the cartoon phenomenon named Fred Jones. Fred Quimby and Chuck Jones were both directors of animation for a number of Tom & Jerry cartoons. Fred Jones was also the name of one of the members of the Scooby Doo gang.
Just like the title and many references throughout the episode, Dean being captioned 'Hunterus Heroicus' and Dr. Mahoney being 'Grotesques Villainus' is a reference to Looney Tunes cartoons.
Dean, Castiel and Sam use the false names 'Crosby, Stills and Nash' after members of the folk rock group of the same name (short 'CSN').