The ba-dum tss comes from live comedy, where drummers in vaudeville and later stand-up clubs played a rimshot sting to mark the end of a joke. The pattern of two rim hits followed by a cymbal splash became a shared signal between performer and audience, even when the joke fell flat. As comedy clips and cartoons reused it, the sound turned into shorthand for a punchline itself. Written online as ba dum tss, it is now used ironically in memes, chats, and edits whenever someone delivers an obvious pun.