3. Anne Carlisle Was Offered the Role of Zuul
The androgynous punk singer had a breakout role in 1982’s Liquid Sky and Reitman pursued her avidly for the small part of Zuul, the servant of Gozer the Gozerian. She turned him down, and the part went to Serbian model Slavitza Jovan.
2. Slimer Is Based on John Belushi
Dan Aykroyd’s Saturday Night Live co-star John Belushi was originally supposed to play Peter Venkman, but when he died in 1982 the role eventually went to Bill Murray. Aykroyd would design the first real ghost the team captured as a gluttonous party guy in homage.
1. “Crossing the Streams” Was Improvised
The final battle with the Stay-Puft Marshmallow Man hadn’t even been written when it was scheduled to be shot, and Harold Ramis and Aykroyd made up the idea of “crossing the streams” on the spot. The crew then wrote and filmed a scene for earlier in the movie to explain the concept.