Nothing is quite as unnerving as the reveal that a horror movie was based on a true story or inspired by real events. Movies are now teased and released with those taglines about real events to further interest horror fans looking for an elevated scare.

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While most of these movies have exaggerated certain details about their stories to make a better horror film, the fact that these events in some way happened in the real world means that the horror contained on the big screen could flow over into its viewers' lives. We'll be exploring a few horror movies today that some fans might not realize were actually inspired by real events.

10 The Exorcist Was Based On The Case Of Roland Doe Who Was Exorcised By Jesuit Priests

Movies The Exorcist Demonic Possession Reagan Floats

1973's The Exorcist by director William Friedkin was based on the book of the same name by William Peter Blatty. The Exorcist terrified audiences with its depiction of a possessed young girl and the priests who attempted to free her from evil. The movie launched a number of sequels and a popular modern TV series.

The book was actually based on the real-world exorcism of young Roland Doe, who was allegedly possessed by a powerful dark force that attracted the involvement of a number of Jesuit priests as well as psychiatric doctors. The case featured a few familiar moments from the movie that included attacks on the priests and vomiting sessions before they were able to exorcise the young boy.

9 Serial Killer Ed Gein Inspired Movies Like The Texas Chainsaw Massacre, Psycho, And Deranged

Leatherface from The Texas Chainsaw Massacre and Norman Bates from Psycho split image

Ed Gein was a convicted serial killer who became known as the Butcher of Plainfield after he murdered two people and desecrated the bodies of others to create items and clothing in his household. Gein's story has inspired multiple movies and characters over the years.

The Texas Chainsaw Massacre used Gein's obsession with body parts to help create the Leatherface character, a detail that also helped inspire Buffalo Bill in The Silence of the Lambs. Gein's relationship with his dead mother was also reimagined for Alfred Hitchcock's iconic Psycho and his character Norman Bates, while films like Deranged were loosely based on Gein as well.

8 A Nightmare On Elm Street Was Inspired By A Series Of Laotian Deaths Caused By Nightmares

A Nightmare on Elm Street

Wes Craven's classic horror A Nightmare on Elm Street features a burnt killer with razors for fingers who terrorized the dreams of teenagers, which might seem too far-fetched to be real. However, the name Freddy Krueger was taken from Craven's childhood bully and the premise of the film was also loosely based on real events.

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Craven had read about a group of Hmong refugees from Laos and Cambodia that escaped their war-torn countries only to suffer traumatic nightmares that made them fear sleep. A child died while having a nightmare, and this was followed by a series of sleep-related deaths. The disorder was named sudden arrhythmic death syndrome and the phenomenon remains largely unexplained.

7 The Amityville Horror Is Based On The Lutz Family's Escape From An Evil Possessed House

The cast of The Amityville Horror with the house in the background

1979's The Amityville Horror explored a family who moved into a new house only to begin experiencing terrifying paranormal events that ultimately drove them away from their home in the middle of the night. The movie was based on the book by Jay Anson that served as an account of the Lutz family's supposedly real experiences in the house before they escaped.

While Anson's account of the Lutzes' story has its detractors, including the Lutzes themselves, the house in Amityville was the scene of a violent series of murders. Ronald DeFeo Jr. murdered his parents and siblings in the middle of the night about a year before the Lutzes moved in. DeFeo's defense involved hearing voices that urged him to kill his family.

6 The Girl Next Door Explored The Brutal Torture And Murder Of A Young Girl By Her Caretaker

Poster for The Girl Next Door

Jack Ketchum's The Girl Next Door is not for casual horror movie lovers and features shocking and grotesque moments that are made even worse with the realization that the movie is based on real events. The Girl Next Door followed sisters who were taken in by a single female caretaker, with the older sister undergoing severe abuse over the course of months, ultimately leading to her death.

The caregiver enlisted not only her own children but others from the neighborhood to torture, beat and molest the young girl before she finally succumbed to her wounds. The Girl Next Door is dedicated to the memory of the deceased girl and doesn't hide the details of the graphic nightmare she lived through, which can make it a difficult watch even for die-hard horror fans.

5 The Haunting In Connecticut Franchise Was Loosely Based On Two Unrelated Paranormal Events

The Haunting of Connecticut franchise split image

2009's The Haunting in Connecticut and the unrelated 2013 sequel The Haunting in Connecticut 2: Ghosts of Georgia were both loosely based on real-world paranormal accounts, though details were changed quite a bit in both cases. The Haunting in Connecticut followed the Snedeker family as they moved into a new house/funeral parlor, leading to their terrifying paranormal claims.

Ghosts of Georgia reimagined the story of the Wyrick family, whose young daughter seemed to be communicating with a deceased elderly man before they were attacked physically by paranormal assailants. Both movies exaggerated events by adding additional horror elements or including connections to the Underground Railroad in the case of Ghosts of Georgia.

4 Fire In The Sky Explored The Alleged Real-World Alien Abduction Of Travis Walton

Travis Walton about to be abducted in Fire in the Sky

While it isn't considered a horror movie by some, there is no doubt that 1993's Fire in the Sky contains a few horror elements that are made even more terrifying by the fact that it is based on a true story corroborated by a group of people. Fire in the Sky explores the alleged alien abduction of a forest worker named Travis Walton who witnessed a UFO along with his logging crew.

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Walton was abducted only to return weeks later with traumatic memories of experimentation aboard the UFO, even as the logging crew dealt with accusations about his disappearance. Fire in the Sky's scenes aboard the ship were greatly exaggerated to induce more fear among fans, though the claims surrounding the alleged abduction were real enough.

3 The Exorcism Of Emily Rose Included Real Audio From Anneliese Michel's Exorcism

A possessed girl in The Exorcism of Emily Rose

2005's The Exorcism of Emily Rose features one of cinema's most terrifying possessions. It also explored the real-world legal case that ensued when two priests were charged with negligent homicide following a "possessed girl's" death following a violent exorcism.

The movie was based on the case of Anneliese Michel, whose recorded exorcism was admitted as evidence in the priests' trial, was played during the film's credits. The same producers also brought fans 2011's The Rite, which followed a young priest as he witnessed a number of alleged possessions and is loosely based on the book written by a real exorcist-in-training.

2 Wolf Creek Is Based On A Series Of Backpacker Murders In Australia By Two Serial Killers

Mick Taylor holding a knife from Wolf Creek

Serial killer Mick Taylor was first introduced in 2005's Wolf Creek before appearing in the 2014 sequel Wolf Creek 2 and a TV series spin-off, which followed a series of backpackers in Australia who were kidnapped and violently tortured & murdered.

Taylor was based on two separate serial killers named Ivan Milat and Bradley John Murdoch, who murdered tourists and backpackers over a span of years. Milat in particular was known for tormenting his victims and even used them for target practice, much like Mick Taylor did in Wolf Creek.

1 The Conjuring Franchise Adapted The Paranormal Investigations Of Ed And Lorraine Warren

Ed and Lorraine Warren from The Conjuring

Fans of The Conjuring franchise are likely already aware of the real-world connections to demonologists (or con men) Ed and Lorraine Warren, whose case files were used in all three of the main series' movies as well as spin-offs like the Annabelle franchise.

The Conjuring movies often ended with pictures and explanations about the real cases, though many of the families the Warrens 'helped' claimed that the couple encouraged them to lie, promising money and, in the trial of Arne Johnson, even an escape from criminal responsibility. Their mere involvement with paranormal stories like the Amityville haunting calls the reality of said tales into question, but they're still amazingly creepy and fun.

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