The music comes from Mike Oldfield's 1973 progressive rock album Tubular Bells, whose opening piano section was used as the main theme for William Friedkin's 1973 horror film The Exorcist. The film's huge success attached those few repeating notes permanently to demonic possession in popular culture. Clips of the theme later spread through Halloween playlists, horror trailers and meme edits, where a short burst is enough to reference the movie without showing it. Its association has lasted for decades because the melody is instantly recognisable and unsettling even out of context.