The Exorcist 1973

Lankester Merrin, a veteran Catholic priest who performed an exorcism in the 1950s, is on an archaeological dig in the ancient Iraq city of Hatra. There he finds an amulet that resembles Pazuzu, a demon of ancient origins with whose history Merrin is familiar.

In Georgetown, actress Chris MacNeil is living on location with her 12-year-old daughter Regan; she is starring in a film about student activism directed by her friend and associate Burke Dennings. After playing with a Ouija board and contacting a supposedly imaginary friend whom she calls Captain Howdy, Regan begins acting strangely, including making mysterious noises, stealing, constantly using obscene language, and exhibiting abnormal strength. Chris hosts a party, during which Regan comes downstairs unannounced, tells one of the guests—an astronaut—that he will die ”up there” and then urinates on the floor. Later, Regan's bed begins to shake violently, further adding to her mother's horror. Chris consults a number of physicians, but Dr. Klein and his associates find nothing physiologically wrong with her daughter, despite Regan undergoing a battery of diagnostic tests.