The theme comes from The Good, the Bad and the Ugly, the 1966 spaghetti western directed by Sergio Leone and scored by Ennio Morricone, starring Clint Eastwood as the gunfighter Blondie. Its whistled melody and spare guitar became shorthand for the whole genre, reused in trailers, adverts and parodies long after the film's release. On soundboards and social video, the short clip survives because it needs no explanation: a few notes instantly signal a showdown, a bluff or an over-the-top entrance.