Sometimes knowing more about a horror film just makes it scarier. It's enough to make you believe that these films were cursed. For example,
9. While filming Poltergeist, Oliver Robins, aka Robbie, truly got choked by the robot clown doll — it wasn't until he turned purple that Spielberg realized what was happening.
10. The actor who played a radiologist's assistant in The Exorcist was a convicted murderer who dismembered and killed gay men in the late '70s.
Paul Bateson murdered and dismembered six men in New York City, while also training to be an X-ray tech (which landed him his spot in the movie)
11. An actual human skull was used in the first model of the iconic Alien creature.
The late artist H.R. Giger was in charge of the design. When asked about the skull, he once said, "Don't ask me where I got it."
Readers submitted movie trivia, and Buzzfeed found sources to see how accurate they are. You can check out all 18 pieces of terrifying trivia plus links to read more about them.