The Exorcist, released in 1973, became one of the most famous horror films ever made, and its opening music quickly became shorthand for demonic possession and supernatural dread. The piano-led theme, Mike Oldfield's Tubular Bells, was already striking on its own, but its use over the film's unsettling opening gave it a lasting association with horror. Since then it has been reused in parodies, Halloween compilations, trailers and reaction videos, because audiences recognise the first notes instantly and understand the tone before a single word is spoken.