It’s been over 30 years since the original Ghostbusters film launched a sequel and a franchise of toys, cartoons, and ecto-flavored beverages. If you were alive in 1984, chances are there isn’t much you DON’T remember about the Ghostbusters phenomenon, but we’ve compiled 7 facts about the spooky hit comedy that might just surprise you.

#1. Dan Aykroyd was following in his grandfather’s footsteps.

Photo Credit: Amazon

Aykroyd’s great-grandfather Dr. Samuel A. Aykroyd was an 18th-century psychic investigator.

His father Peter claims he’s been regularly communicating with the dead since he was 8 years old, and at one point tried to build a device that could capture ghost’s voices, but stopped when the ghosts told him that it would be impossible.

#2. The film was inspired by an article in a journal from the American Society for Psychical Research.

Photo Credit: Alphr

Shortly after leaving Saturday Night Live, Aykroyd read an article on quantum physics and parapsychology in a journal from the American Society for Psychical Research and a light bulb went off in his big cranium. He decided to write a screenplay that combined psychic research and old-style comedy. Think of a cross between Sherlock Holmes and the Marx Brothers.

By the way, that photo features Sigmund Freud (front row, left) and Carl Jung (front row, right), both members of the Society. Some pretty heavy hitters!

#3. Harold Ramis was pretty much the opposite of Aykroyd, and that was perfect.

Photo Credit: Columbia Pictures

Ramis was a healthy skeptic, but he did have an interest in early civilizations and a detailed knowledge of the occult. Put those tastes together, and you have the essential story for Ghostbusters: a slapstick, science-driven exploration of the occult where an evil god is summoned by an ancient Sumerian cult.

But, things still needed to be distilled a bit more before the script was ready for action.

By the way, did you know that the original script for the film would have been the most expensive movie in history?

Find out why after the jump!