Trivia: The "Demonic Balloons" that attack the Ghostbusters are almost direct re-creations of real Macy's Thanksgiving Day Parade balloons from the 1930's. The filmmakers decided to use the real designs in order to represent the "spirits" of New York's history... and also because they were quite eerie and unsettling.
Trivia: Even though this film isn't connected to the original films, Harold Ramis, Bill Murray, Dan Akroyd, Annie Potts, Ernie Hudson and Sigourney Weaver all make cameos in this film. Harold Ramis as a bust in the hall of the university where Erin was going to teach; Bill Murray as supernatural debunker Dr. Martin Heiss who dies after Mayhem kicks him out the window; Dan Aykroyd as a cab driver; Annie Potts as the snooty hotel receptionist; Ernie Hudson as Patty's uncle who gave her the hearse to drive; Sigourney Weaver as Holtzman's mentor Rebecca Gorin.
Trivia: In order to enhance the 3D effects in the film, some elements like slime and the proton beams are rendered to go "beyond the borders" and into the black matting that is present at the top and bottom of the image. This effect is also maintained in some 2D home-video releases of the film.
Kevin: Can I bring my cat to work? He has terrible anxiety problems.
Abby Yates: Oh, I'd love to let you bring your cat to work, but I have a terrible cat allergy.
Kevin: I don't have a cat. He's a dog. His name is My Cat.
Abby Yates: You named your dog My Cat?
Kevin: Mike Hat.
Erin Gilbert: First name Mike, last name Hat?
Kevin: Well, his full name is Michael Hat.