13 Iconic Horror Movies Inspired by Real-Life Events

What's real: Another book-to-movie adaptation, The Exorcist comes from a 1971 novel by William Peter Blatty. The origin of Blatty's book, though? It's actually inspired by the 1949 exorcism of a young boy who's since been referred to using the pseudonym "Roland Doe." There are plenty of online iterations of the story, including a piece from Yahoo that cites Doe's alleged "strange welts" and other markings, his purported aversion to anything sacred, and a strange, guttural speaking voice he sometimes presumably used. The Smithsonian Channel even recounted the exorcism story with witness accounts.