The ba-dum-tss rimshot comes from live comedy, where a drummer would punctuate a comedian's joke with a quick snare and cymbal hit, a technique dating back to vaudeville and early stand-up clubs. As comedy moved to television, radio and later online video, the sting became shorthand for a punchline, even when the joke was intentionally terrible. It spread through soundboards, meme edits and reaction videos, where its two-second length makes it easy to drop into almost any clip. Today it remains a universal signal that a joke has just been told.