15. The Entity (1981)
The horror movie: Based on the novel by Frank De Felitta, Sidney J Furie's adaptation follows single mother Carla Moran (Barbara Hershey), who victimised by a violent, sexually-abusive poltergeist. Yeah, it's not a nice premise, but luckily the OTT soundtrack whenever the 'entity' shows up adds a bit of levity.
The true story: In 1974, paranormal investigators Kerry Gaynor and Barry Taff visited the home of Culver City resident Doris Bither, who claimed that she'd been assaulted by some sort of entity. While at Bither's home, Gaynor and Taff allegedly saw objects moving of their own accord and a strange apparition.
14. The Town That Dreaded Sundown (1976)
The horror movie: A micro-budget indie slasher that pre-dates Halloween (but not Black Christmas). A hood-wearing killer terrorises a town in 1946 Arkansas, while a Texas Ranger attempts to bring him down.
The true story: A spate of murders in the 1940s, called the Texarkana Moonlight Murders, were carried out by the so-called Phantom Killer. Over a ten week period, the Phantom Killer murdered eight people... and the culprit was never found. Shudder.
13. Child's Play (1988)
The horror movie: Serial killer Charles Lee Ray (Brad Dourif) transfers his soul into a doll using spooky voodoo when he's mortally wounded by the cops. And just because he's trapped in a doll doesn't mean Charles, now Chucky, is going to give up his old ways any time soon.
The true story: Writer Don Mancini based the Child's Play script on the case of a nurse who allegedly put a voodoo curse on the author Robert Eugene Otto, transforming one of his childhood dolls into a night-time menace.
12. Them (2006)
The horror movie: A gang break into the remote home of Lucas (Michal Cohen) and Clementine (Olivia Bonamy) for a night of nerve-shredding terror. You want fist-chewing tension? You got it.
The true story: Directors David Moreau and Xavier Palud based their film on the case of an Austrian couple who were staying at their Romanian holiday home when they were attacked and killed by three teenagers.
11. Henry: Portrait of a Serial Killer (1986)
The horror movie: Follows the exploits of Henry (yes, that's The Walking Dead's Michael Rooker), whose hobby just so happens to be killing people. He changes his MO every time as he stalks then kills his victims. Trust us, this is grisly stuff.
The true story: The character of Henry is loosely based on the stories of real-life serial killer Henry Lee Lucas, who claims to have killed up to 3,000 people. Though that remains unverified (and Lucas even recanted those statements), he was at the centre of 11 murder cases and blamed being bullied as a child as part of the reason he became a killer.
10. I Spit on Your Grave (1978)
The horror movie: This rape revenge flick went on to become a cult classic though it was condemned on release as tasteless and violent. The film follows writer Jennifer Hills (Camille Keaton), who heads off on a retreat in Connecticut, where she's brutally assaulted by a gang of locals.
The true story: Writer/director Meir Zarchi took inspiration from one of his own experiences in Central Part in 1974. There, he came across a woman who had been raped and beaten, but when he took her to the police, she was allegedly treated unfairly. Zarchi stated that the character of Jennifer Hills came out of that incident: she's somebody who takes matters into her own hands.
9. The Conjuring (2013)
The horror movie: Directed by Saw mastermind James Wan, Patrick Wilson and Vera Farmiga star as paranormal investigators Ed and Lorraine Warren who are called in when a family's new home starts behaving very strangely.
The true story: Ed and Lorraine Warren were real-life investigators who claim to have investigated over 10,000 cases in their heyday. One of those cases was that of the Perron family, whose new Rhode Island home was being haunted by malevolent a witch called Bathsheba Sheran, who had lived there in the 19th century.
8. The Exorcism of Emily Rose (2005)
The horror movie: A courtroom horror in which Erin Christine Bruner (Laura Linney) defends priest Richard Moore (Tom Wilkinson) after he performed an exorcism that resulted in a death. Flashback scenes reveal the experiences of the girl in question, Emily Rose (Jennifer Carpenter).
The true story: Inspiration hails from the case of a 16-year-old German girl called Anneliese Michel. After experiencing a major epileptic seizure, she began to suffer from intense depression and suicidal thoughts. After being admitted to a psychiatric hospital, the devout teen began to hear voices and have aversions to religious objects. The church stepped in to perform an exorcism, which took ten months to accomplish, and Michel died shortly afterwards from malnutrition.
7. Wolf Creek (2005)
The horror movie: When their car breaks down in the Australian outback, three backpackers accept help from a bushman who kidnaps and tortures them in Wolf Creek National Park.
The true story: Two men provided the inspiration for Greg McLean's film. First there was Ivan Milat who, in the nineties, would kidnap hitchhikers and torture them in the woods. And secondly Bradley John Murdoch, who was responsible for killing a British tourist.
6. The Amityville Horror (1979)
The horror movie: When the Lutz family move into a new home in Amityville, New York, strange events lead them to believe that something terrible is lurking in the house. Then they discover that it used to belong to Robert DeFeo, a man who killed his entire family with an axe 13 months previously.
The true story: A case investigated by paranormal detectives Ed and Lorraine Warren, the book on which the film's based (by Jay Anson) is reportedly based on the experiences of the real Lutz family. That said, there have been numerous lawsuits about the story's legitimacy over the years. Rumors suggest that the Warrens and Anson made the whole thing up.