Horror fans are unlike any other breed of cinephile. We go to great lengths to unearth little known facts about our favorite feature films. Because of that, it’s a challenge to find trivia that will pass fact checking and surprise dedicated fans. But, in spite of that, we have taken it upon ourselves to attempt to unearth some lesser-known details about William Friedkin’s The Exorcist. Read on for the top ten things you probably didn’t know about The Exorcist.

Linda Blair didn’t do all of the possessed voice acting

An actress named Mercedes McCambridge who reportedly chain-smoked and ate raw eggs to get that guttural tone we hear in the film did the majority of the scenes where Regan speaks in a possessed voice. McCambridge’s involvement was initially kept a secret and it is largely speculated that the announcement that Blair didn’t use her own voice for most of the possession scenes is what cost her the Oscar. McCambridge reportedly had to sue Warner Brothers to get screen credit for the voice acting she did in the film.

William O’Malley, who played Father Dyer, is an actual priest

The Exorcist is his only acting role to date. He reportedly still teaches at Fordham University.

It took three hours a day to get Max Von Sydow into makeup

The actor was playing a character much older than his 43 years, so a series of makeup effects were applied every day of shooting to age his face to fit the character.

There are as many as nine deaths associated with the film

Many of the deaths were of friends and family members of the cast and crew. The film had a large number of people involved and was shot over a long period of time; so many people believe that the curse of The Exorcist is merely an attempt to sensationalize a series of unrelated events.

The crab-walking scene was deleted due to the visibility of the support wires

The scene was added back in to the extended cut of the film in 2000 when advances in technology easily allowed for the wires to be edited out.

Linda Blair reportedly received death threats from several religious institutions

As a result of the threats on young Blair’s life, the studio is said to have provided the young actress with bodyguards for several months after the production was complete.

The film and book from which it was adapted are based on a true story

The True story behind The Exorcist is that of a young boy that was possessed in Cottage City, Maryland in 1949. It’s been said that the film follows the actual events fairly closely.

Linda Blair may not have been the first choice to play Regan

The role was reportedly offered to the late Dana Plato before the part was given to Blair. However, William Peter Blatty denies there is any truth to that rumor and suggests that Plato fabricated the story.

John Boorman declined an offer to direct The Exorcist

It was reported that the director turned the opportunity down because he thought that the film promoted cruelty towards children. It would seem that he later regretted it, as Boorman wound up directing the vastly inferior second installment in the series.

Billy Graham renounced the film as pure evil

It’s been said that the Evangelical Preacher claimed there was an actual demon living in the celluloid of the film but we were unable to locate any direct quote where the Reverend is actually cited as saying other than the film is rooted in pure evil.

Related: Why Exorcist III is One of the Most Overlooked Horror Films of the ’90s