The dreamlike area in which Peter finds himself is modeled after the painting "The Persistence of Memory" by Salvador Dalí.
The spirit from this episode is one of the few ghosts to escape from the Ghostbusters' trap after being successfully trapped. He is the only spirit to escape from traps more than twice.
All of "Calimari's" aliases are named after Italian food.
Dr. Calimari is a hypnotist, just like Dr. Caligari from The Cabinet of Dr. Caligari (1920), the film referenced in the title.
According to an interview, Matt Edens pitched the Houdini premise of the episode to his two older brothers who ended up writing it. Matt Edens was paid $100 from each brother.