The ba-dum-tss rimshot comes from live comedy drumming, where a drummer would play a short fill to mark the end of a joke and cue the audience to laugh. The pattern moved from stage and variety shows into television, cartoons and stand-up, becoming a universal shorthand for a punchline, especially a deliberately corny one. Online, it spread through meme videos, reaction clips and soundboards, where its short length makes it easy to drop over any joke. It endures because listeners recognise it instantly, even without seeing a drummer.