The Real Story: The character Norman Bates was inspired by Ed Gein, a Wisconsin man who was arrested in 1957 for committing two murders and digging up the corpses of countless other women who reminded him of his dead mother. He skinned the bodies to make lamp shades, socks and a "woman suit" in hopes of becoming a woman. He was found to be insane and spent the rest of his life in a mental institution.
The Real Story: William Peter Blatty, screenwriter and author of the novel The Exorcist, was inspired by an article he read in college at Georgetown University about an exorcism performed on a 13-year-old boy in Mount Rainier, Maryland in 1949. The story's details have been muddled through the years -- perhaps intentionally so, in order to protect the family -- but the boy's actual home lay in Cottage City, Maryland, and the exorcism was performed in St. Louis. Evidence points to the boy's behavior not being nearly as outrageous or supernatural as was portrayed in the film.
The Real Story: Again Ed Gein (see Psycho), whose exploits also inspired the films Deranged and, in part, The Silence of the Lambs.
The Real Story: Screenwriter and novelist Peter Benchley was inspired in part by a series of shark attacks that plagued the New Jersey shore in 1916. Over a 12-day period in July of that year, five people were attacked, four of whom died. A seven-foot-long great white shark was killed on July 14, and its stomach was found to contain human remains. To this day, there is a debate over whether or not that shark was the culprit -- some scientists argue that it was probably a bull shark -- but no further attacks were reported that summer after it was killed.
The Real Story: Frank De Felitta was inspired to write the novel -- and later the movie script -- after he heard his six-year-old son, Raymond, who'd never taken piano lessons, playing music perfectly on the family piano. De Felitta consulted a Los Angeles occultist, who called Raymond's talent as an "incarnation leak," explaining that the boy had lived many lifetimes. The incident led to the author's personal belief in reincarnation.
The Real Story: The movie was inspired by the legend of Alexander "Sawney" Bean, a Scottsman of the 15th or 16th century who reportedly headed a 40-person clan that killed and ate over 1,000 people, living in caves for 25 years before being caught and put to death. His life has inspired numerous stories and films worldwide, including The Hills Have Eyes and the British film Raw Meat, but most serious historians today don't believe that Bean ever existed.
The Real Story: Perhaps the most notorious horror movie "based on a true story," the film is based on a self-proclaimed nonfiction book describing what George and Kathy Lutz experienced during their four weeks in the house, including disembodied voices, cold spots, demonic imagery, inverted crucifixes and walls "bleeding" green slime. Most, if not all, of the events portrayed in both the book and the movie have been called into question by investigators, and it is widely believed that the entire incident was a hoax.
The Real Story: In 1974, paranormal researchers Kerry Gaynor and Barry Taff investigated the case of a woman believed to be named Doris Bither. Bither lived in Culver City, California and claimed to have been physically and sexually assaulted by an entity. Gaynor and Taff witnessed objects move in her house, captured photos of floating lights and saw a humanoid apparition, but they never saw it assault the woman and never tried to capture it. Gaynor stated that the attacks diminished when Moran moved.
The Real Story: On July 19, 1975, the decomposing, emaciated bodies of 45-year-old twin gynecologists Stewart and Cyril Marcus were discovered in their apartment. The cause of death was extreme withdrawal due to an addiction to barbiturates. It's unclear what led to their shocking state.
The Real Story: In the rainy summer of 1816, Percy Shelley and Mary Godwin (soon to be Shelley) visited Lord Byron at his Swiss villa. Due to the rain, they stayed indoors discussing the animation of dead matter and reading German ghost stories. Byron suggested they each write their own supernatural tale, and Godwin came up with Frankenstein, while Byron wrote what would later be adapted by Polidori into The Vampyre.