JB Smoove is the American comedian and actor best known as Leon Black on HBO's Curb Your Enthusiasm, a role he has played since 2007. The exact recording this two-and-a-half-second clip is taken from is not documented, so its precise origin remains unclear. What is clear is how it travels: the deadpan dismissal has become a handy reaction sound across memes, edits and streams, where two words shut down anything absurd. Its staying power comes from Smoove's delivery, which turns a plain phrase into a punchline that needs no context.