Horror movies are even more chilling when they’re based on actual events. Here are the 9 best scary movies based on real life happenings. Serial killer Ed Gein served as inspiration for this film’s antagonist. Unexplained paranormal events that took place in 1958 inspired this cult classic. This thriller was inspired by a young Cambodian boy who died in his sleep. This villain is partially based on a doctor who dismembered his boyfriend.