The sound comes from Squid Game, the South Korean survival drama on Netflix in which indebted players compete in children's games for a cash prize. Inside the game, players press an O button to vote to continue, a mechanic that became a recognisable shorthand for agreeing to keep playing despite the danger. Clips of the vote spread through reaction videos, parodies and short-form edits, where the short tone now signals a yes vote even outside the show. Its simplicity keeps it useful for polls, challenges and choice-based content.