Level 3 Fright, aka There's No Coming Back From This, I'm in a Perpetual State of Terror: The Exorcist (1973)
This one is for the hardcore horror fiends. This petrifying tale centres around a young girl named Regan (Linda Blair) who has been possessed by the devil. She levitates, she controls things with her mind, and she scars pretty much anyone who dares to watch this film. Local priest Damien Karras (Jason Miller) and exorcist expert Father Lankester Merrin (Max von Sydow) try their best to extract the demonic being inhabiting Regan's body, but it's a horrifyingly complicated feat.