While most horror movies are complete works of fiction, the genre occasionally offers up stories that are based on terrifying and jaw-dropping real-life events, like the nine collected here.

1. A NIGHTMARE ON ELM STREET (1984)

Premise: A supernatural killer stalks his prey while they dream during deep sleep.

Real-Life Inspiration: Wes Craven based A Nightmare on Elm Street on a series of newspaper articles from the Los Angeles Times about a strange phenomenon where young Asian refugees would mysteriously die in their sleep. It was reported that many would refuse to sleep, citing terrifying nightmares that they feared would lead to death.

According to Craven, the paper "never correlated [the three articles], never said, ‘Hey, we’ve had another story like this'":

The third one was the son of a physician. He was about twenty-one; I’ve subsequently found out this is a phenomenon in Laos, Cambodia. Everybody in his family said almost exactly these lines: "You must sleep." He said, "No, you don’t understand; I’ve had nightmares before—this is different." He was given sleeping pills and told to take them and supposedly did, but he stayed up. I forget what the total days he stayed up was, but it was a phenomenal amount—something like six, seven days. Finally, he was watching television with the family, fell asleep on the couch, and everybody said, "Thank god." They literally carried him upstairs to bed; he was completely exhausted. Everybody went to bed, thinking it was all over. In the middle of the night, they heard screams and crashing. They ran into the room, and by the time they got to him he was dead. They had an autopsy performed, and there was no heart attack; he just had died for unexplained reasons. They found in his closet a Mr. Coffee maker, full of hot coffee that he had used to keep awake, and they also found all his sleeping pills that they thought he had taken; he had spit them back out and hidden them. It struck me as such an incredibly dramatic story that I was intrigued by it for a year, at least, before I finally thought I should write something about this kind of situation.

2. CHILD'S PLAY (1988)

Premise: A serial killer's soul possesses a toy doll and wreaks havoc.

Real-Life Inspiration: In 1909, Key West painter and author Robert Eugene Otto claimed that one of his family's servants placed a voodoo curse on his childhood toy, Robert the Doll. Supposedly, the doll would mysteriously move from room to room, knock furniture over, and conduct conversations with Otto. Robert the Doll was left in the attic until Otto's death in 1974, when new owners moved into his Florida home. The new family also claimed mysterious activities would happen in the house connected to the doll. Today, Robert the Doll is on display at Key West's Fort East Martello Museum.

3. THE AMITYVILLE HORROR (1979)

Premise: A young family moves into a house where a murder was committed, and experiences strange and terrifying occurrences.

Real-Life Inspiration: Based on the book of the same name, The Amityville Horror follows the paranormal events that terrorized the Lutz family. In 1975, the family moved into 112 Ocean Avenue where, unbeknownst to them, Ronald DeFeo, Jr. had brutally murdered his family 13 months before they arrived. While in their new home, the family claimed that they saw green slime on the walls and red-eyed pigs staring into their kitchen and living room. After less than a month, the Lutz family moved out of the small town of Amityville, New York.

4. PSYCHO (1960)

Premise: A secretary goes on the run after she steals $40,000, only to wind up in a motel where the innkeeper and his mother are more than they appear to be.

Real-Life Inspiration: Psycho's Norman Bates is loosely based on convicted murderer and grave robber Ed Gein, who, during the late 1950s, killed women and unearthed corpses in Wisconsin. He also fashioned human skin into tiny keepsakes and knickknacks, such as face masks, belts, and chair coverings. Psycho's novelist Robert Bloch based Bates on Gein, but changed the character from a grave robber and murderer into a serial killer who dressed like his mother. The Texas Chainsaw Massacre and The Silence of the Lambs also based their serial killers—Leatherface and Buffalo Bill, respectively—on Gein.

5. THE EXORCIST (1973)

Premise: Two Catholic priests perform an exorcism on a young girl who is possessed by the devil.

Real-Life Inspiration: The Exorcist's author and screenwriter William Peter Blatty based the novel and film on a 1949 article in The Washington Post headlined, "Priest Frees Mt. Rainier Boy Reported Held in Devil's Grip." The article followed Jesuit priests William S. Bowdern, Edward Hughes, Raymond J. Bishop, and Walter H. Halloran participating in the rite of exorcism on a boy with the pseudonym "Roland Doe" in Maryland. According to the priests, they allegedly experienced the boy speaking in tongues, the bed shaking and hovering, and objects flying around during the ordeal. The exorcism was one of three official Catholic Church-sanctioned exorcisms in the United States at the time.

"Maybe one day they’ll discover the cause of what happened to that young man, but back then, it was only curable by an exorcism," William Friedkin, the director of The Exorcist, told Time Out. "His family weren’t even Catholics, they were Lutheran. They started with doctors and then psychiatrists and then psychologists and then they went to their minister who couldn’t help them. And they wound up with the Catholic church. The Washington Post article says that the boy was possessed and exorcised. That’s pretty out on a limb for a national newspaper to put on its front page ... But you’re not going to see that on the front page of an intelligent newspaper unless there’s something there."

6. THE GIRL NEXT DOOR (2007)

Premise: An aunt tortures and abuses her niece, and a neighborhood boy fails to alert the authorities.

Real-Life Inspiration: Based on Jack Ketchum's novel of the same name, The Girl Next Door is based on the murder of Sylvia Likens, a 16-year-old girl from Indiana in 1965. Sylvia and her sister Jenny were left in the care of Gertrude Baniszewski, a family friend, when their parents left town as traveling carnival workers. Baniszewski, along with her children and a few neighborhood kids, locked Sylvia in the basement, where they tortured and abused her until she died of a brain hemorrhage and malnutrition.

7. THE CONJURING (2013)

Premise: Two paranormal investigators help a family who move into a secluded home plagued by weird events.

Real-Life Inspiration: The Conjuring is based on real-life paranormal investigators Ed and Lorraine Warren and their experience with the Perrons, a family who moved into a Rhode Island farmhouse and experienced ghostly and terrifying occurrences in 1971.

"When Insidious came out and was successful the story about the Warrens came to me and I was like, 'Oh, my gosh, this is really cool,'” director James Wan told Entertainment Weekly in 2013. "But I didn’t just want to make another ghost story or another supernatural film. One thing I had never explored was the chance to tell a story that’s based on real-life characters, real-life people. So those were the things that led me to The Conjuring."

The Warrens also had a possessed Raggedy Ann doll that was the inspiration for the spin-off film Annabelle.

8. OPEN WATER (2003)

Premise: Two scuba divers become stranded in shark-infested waters after their tour group accidentally leaves them behind.

Real-Life Inspiration: Open Water is based on American tourists Tom and Eileen Lonergan, a couple who were lost at sea when their tour group left them behind while scuba diving near the Great Barrier Reef in Australia in 1998. When the diving company realized the mistake two days later, they organized a search party, but the Lonergans were never found. The only thing that was found was a diver's slate (an underwater communication device) with a S.O.S. message on it that read, "[Mo]nday Jan 26; 1998 08am. To anyone [who] can help us: We have been abandoned on A[gin]court Reef by MV Outer Edge 25 Jan 98 3pm. Please help us [come] to rescue us before we die. Help!!!"

9. THE BLOB (1958)

Premise: A mysterious alien life-form terrorizes a small town and consumes everything in its path as it grows bigger and bigger.

Real-Life Inspiration: Believe it or not, The Blob is based on a New York Times article from 1950 titled, "A ‘Saucer’ Floats to Earth And a Theory Is Dished Up." The story followed four Philadelphia police officers who came into contact with a strange gooey material, which is now believed to be "Star Jelly," a transparent gelatinous substance. When one of the officers tried to move the goo, it started to dissolve and evaporate, so there was nothing to show the FBI when they arrived on the scene except a spot on the ground.