Don't worry: it's just a movie. That's typically what we tell ourselves when watching a particularly pant-browning horror film. It's all well and good doing that, except when the film we're watching is real. See, while many products of the silver screen are elaborate works of fiction, like Guardians of the Galaxy, Lord of the Rings, and One Direction: This Is Us, some are based on actual events... things that really happened. And some of them are utterly chilling.
What follows is a list of 25 movies that are based on real-life events. So read on and drink in the horror, safe in the knowledge that you'll never sleep quite as comfortably ever again. The truth really is stranger, sorry, scarier than fiction.
25. Audrey Rose (1977)
The horror movie: Horror connoisseur Robert Wise directs a supernatural mindfuck. Anthony Hopkins is on deliciously sinister form as Elliot Hooper, who believes that the daughter of a young couple is his dead wife reincarnate. Yeah, that's just weird.
The true story: Things only get weirder when you look into the creation of Frank De Felitta's novel, on which this is based. Felitta's six-year-old son could play the piano perfectly, despite the fact that he'd never had a single lesson in his short life. The bizarre development led Felitta to contact an occultist and resulted in the author's belief in reincarnation.
24. A Nightmare on Elm Street (1984)
The horror movie: American teenagers are haunted by the knife-fingered ghost of a scarred serial killer who goes by the name of Freddy Krueger (Robert Englund). Going to sleep won't save you. There will be blood. Lots and lots of blood.
The true story: Though the story itself is entirely fictional, writer-director Wes Craven has admitted that he was at least partly inspired by an LA Times article about a group of Cambodian immigrants who all died while in the throes of a nightmare.
23. The Girl Next Door (2007)
The horror movie: Not the Emile Hirsch rom-com, but a traumatic horror flick in which Meg (Blythe Auffarth) is kidnapped by her neighbours and submitted to extreme torture in their cellar.
The true story: The shocking events in The Girl Next Door were loosely inspired by the death of Sylvia Likens, who was tortured and eventually killed by her next-door neighbour Gertrude Baniszewski in 1965. She was just 16 years old at the time of her death, when she and her sister were left in the care of Baniszewski while her parents worked away. The crime was described as "the most terrible crime ever committed in the state of Indiana" by the prosecutor during the court case.
22. Open Water (2003)
The horror movie: Scuba divers Daniel Kintner (Daniel Travis) and Susan Watkins (Blanchard Ryan) are stranded in shark-infested waters when they're left behind during a sea-bound excursion.
The true story: American tourists Tom and Eileen Lonergan disappeared near the Great Barrier Reef in January 1998 when a diving company left them behind after failing to take a headcount. Two days later, the company realised their mistake (sheesh) and manned a search, but the Lonergans were never found.
21. The Strangers (2008)
The horror movie: House invasion horror starring Liv Tyler and Scott Speedman as a couple who go to stay at a summer home, only to fall victim to a trio of menacing, mask-wearing psychopaths.
The true story: Director Bryan Bertino revealed the movie's premise was based on an incident that happened to him; as a kid a stranger appeared at his door, asked for someone who didn't live there and left. He later found out that a series of break-ins occurred in his neighbourhood that night. On top of that, he also drew inspiration from the infamous Manson killings, carried out by the minions of occultist Charles Manson.
20. Borderland (2007)
The horror movie: A trio of college buddies visit a Mexican border town hoping for a break from the lawfulness of the States. They're shortly kidnapped by a human-sacrificing cult who offer up 'gifts' to a voodoo god so they can smuggle drugs over the border. Bummer.
The True Story: Berman's film was inspired by the story of Adolfo de Jess Constanzo, a leader of a cult where human sacrifice was openly practiced. Constanzo kidnapped and killed members of drug cartels when he was denied a share in the business. The mutilation he carried out was so horrendous we'll refrain from detailing it here.
19. The Mothman Prophecies (2002)
The horror movie: Richard Gere plays John Kline, a reporter who investigates the mysterious Mothman, who's said to haunt the town of Point Pleasant. Is he just a myth, though?
The true story: Author John Keel's book was inspired by his own investigations into the Mothman in Point Pleasant in 1966 and 1967. Several locals reported seeing a winged creature with red eyes over the course of a year. In the book, Keel eventually links his detective work with that of others, in particular the Silver Bridge Collapse in 1967.
18. The Possession (2012)
The horror movie: A young girl discovers a dybbuk's old box at a second-hand sale. After opening it, her behaviour becomes increasingly uncontrollable. Is she possessed? Or is she merely struggling to deal with the divorce of her parents, Clyde (Jeffrey Dean Morgan) and Stephanie Brenek (Kyra Sedgwick)?
The true story: Director Ole Bornedal says the story of the dybbuk box was his inspiration for the film. Jewish folklore states that a dybbuk is malicious spirit that can possess the living. Numerous owners of one specific box that went for sale on eBay reported strange phenomena happening around it.
17. The Hills Have Eyes (1977)
The horror movie: Freaky desert flick in which a family stumbles across a brood of flesh-eating weirdos out in the wilds of California. Those same weirdos then eat the family's flesh.
The true story: Wes Craven wrote the script for this after getting inspired by the legend of Alexander 'Sawney' Bean, the head of a 16th century clan of cave-dwellers. They lived there for 25 years, chowing down on an estimated 1,000 people before they were found out and killed.
16. The Blob (1958)
The horror movie: Pretty much the weirdest alien invasion movie ever, but also one of the (unintentionally?) coolest, as an alien blob of jelly descends on planet Earth and begins devouring the inhabitants of a small US town.
The true story: Meteoric jelly is apparently a commonly-found substance, referred to as 'star jelly'. The Blob was inspired by an event in 1950, when Philadelphia cops discovered a massive glob of the jelly. It dissolved when they tried to move it. Which is preferable to being eaten by it, I suppose?