Abby, Erin, Jillian, and Patty replaced Peter, Ray, Egon, and Winston, but there's one male character that Ghostbusters co-writer and director Paul Feig knew he wouldn't recast: Slimer. The "ugly little spud" has been involved in nearly every Ghostbusters property, including the reboot out today. But where did he come from?

According to Feig, who created a backstory with Ghostbusters co-writer Katie Dippold, Slimer was a gangster executed for killing a waiter who screwed up his order. Slimer started his afterlife as a more traditional ghoul, but was disfigured when the Ghostbusters were called to the restaurant he was haunting.

"When the Ghostbusters come in, they haven’t quite tested their equipment yet, so they haven't got the levels right," Feig says. "The proton beams are too hot, so it blows his legs off. Then it turns him green. He starts to distort, and so he becomes Slimer. Then he escaped out into the world."

The backstory didn't make it into the final film, but the green guy did. Find out more about the untold history of the ghost-of-mercurial-gangsters-past in the video above.