In today's busy world, it's easy to forget that the threat of demonic possession is real, constant, and terrifying. Thankfully, the Fathers of Morality in Hollywood (and abroad) aren't afraid to tackle this problem spinning-head-on in films about demonic possession, the scariest of which could make even the most hardened secularists give this whole "church" thing a try.
Maybe there were movies about demonic possession before "The Exorcist," maybe there weren't. Just like there may have been chocolate bars before Hershey, or rock bands before The Beatles. What difference does it make? "The Exorcist," with its absolutely and unbendingly realistic tone, is widely considered one of the scariest movies ever made. And it remains the first thing most people think about when they hear the words "demonic possession." Unless of course they're unlucky enough to actually know someone who's been possessed by a demon.
"The Evil Dead"
Almost as legendary is Sam Raimi's "The Evil Dead." A word of warning: If you only know Sam Raimi by his later, more humorous horror movies (like "Evil Dead II" or "Drag Me to Hell"), you may be surprised by how scary "The Evil Dead" really is. In it, Loveable Ash and a group of friends travel to an isolated cabin in the woods, where they make the completely-rational decision to read the Necronomicon out loud, which causes all sorts of demons to descend upon them and wreak havoc. It's pretty unpleasant.
"Twitch of the Death Nerve"
The killer in Mario Bava's "Twitch of the Death Nerve" (also known as "Bay of Blood") isn't explicitly a demon – but if you've got a better word for a kind of amorphous evil force that takes control of people and forces them to kill their loved ones and acquaintances, please feel free to substitute it at your convenience. Often considered one of the first slasher movies, it's also an unexpectedly subtle look at demon possession.
"Lisa and the Devil"
A more explicit look at Satan's work on Earth from Mario Bava can be found in "Lisa and the Devil," which as you can see from the title is explicitly about the Devil. And who better to bring Old Scratch himself to life than Telly Savalas? There's something weird about that guy. Interestingly, the movie was given a makeover by the studio and released as an "Exorcist" knock-off entitled "House of Exorcism." As knock-offs go, it's pretty good, although not as good as:
"The Exorcist III"
After the alternating boredom and bafflement that accompanies watching "Exorcist II," you could be forgiven for thinking "Exorcist III" is a creatively uninspired attempt to cash in on the original's reputation. You'd be wrong, though – directed by William Peter Blatty, author of the original novel, it has a creepy and disturbing style all its own. But know this: You will not look as cool as Brad Dourif does if you get possessed by a demon. No one would.