15 Facts You Didn't Know About the Original 'Ghostbusters,' From Bill Murray's Secret Role to the Reptile That Almost Terrorized New York

Slimer (a.k.a. Onionhead) vs. Bill Murray in ‘Ghostbusters’ (Columbia Pictures/GIF via HTMLgiant.com)

Imagine Eddie Murphy and his fellow paranormal firefighters battling a motorcycle-riding skeleton and a giant lizard monster from their gas-station base in a futuristic New Jersey. Who you gonna call? Ghost Smashers!

By the time it became an instant classic upon its release in 1984, Ghostbusters had morphed through radically different iterations, featuring bonkers plot points and unrecognizable creatures. Those mind-blowing details are chronicled by Ghostbusters: The Ultimate Visual History, author Daniel Wallace’s revelatory, self-explanatory new book due out this week, just in time for Halloween.

“I’m a huge Ghostbusters fan, and pretty much every page in this book contains some sort of fact that either wowed me or gave me an acute case of nostalgia,” Wallace tells Yahoo Movies.

Thom Enriquez’s Mr. Stay Puft concepts (via ‘Ghostbusters: The Ultimate Visual History’)

Indeed, from star and co-writer Dan Aykroyd’s sci-fi-tinged original treatment and the casting process to concept art and deleted scenes, the new Ghostbusters tome is full of behind-the-scenes factoids that will astound even the movie’s biggest fans. Here are 15 to ponder:

1. Dan Aykroyd truly believes in ghosts. He wrote Ghostbusters in part because he didn’t think it was right for skeptics to dismiss the paranormal. “What if you advertised on TV or in the Yellow Pages and said, ‘Hey, we believe you, we understand you’” the actor is quoted as saying in the book. “That was the birth of the commercial enterprise of ghostbusting.”

2. Dan Aykroyd dreamed up his original treatment for Ghostbusters around 1981 — the original title was Ghost Smashers. Per Wallace, the story “threw audiences into the deep end of the pool, with a near-future setting and innumerable procedural details concerning high-tech parapsychological tactics. The heroes operated out of a converted New Jersey gas station and faced spectral threats, including a skeletal biker who terrorized a small town.” In the climax, “the Ghostbusters traveled to alternate dimensions.” As director Ivan Reitman relates in the book’s introduction, he received an updated outline in 1983 featuring “a group of men, acting much like firefighters, [who] would trap and catch ghosts as part of a new protective emergency service for the universe at large.” Reitman suggested that Aykroyd reconceive “the story in modern-day Manhattan and frame the adventure as a 'going into business’ tale.” He also encouraged Aykroyd to bring in Harold Ramis as a co-writer. The brain trust was set and together over a two-and-a-half week vacation with their families in Martha’s Vineyard, the trio reshaped the story.

3. The script was written for Aykroyd’s fellow Blues Brother John Belushi to co-star as Peter Venkman, but Belushi died of an overdose in 1982. Aykroyd then zeroed in an Eddie Murphy to co-star.  At one point another Saturday Night Live colleague, Chevy Chase, was eyed for the role — the book includes an excerpt of a script that mentions a “female ghost (romantic-sexy) [that] seduces Chevy Chase.” (Bill Murray, of course, ultimately came aboard.)