The sound comes from It's Always Sunny in Philadelphia, the long-running American sitcom built around a group of self-interested friends running a Philadelphia bar. Rickety Cricket, a former priest whose life unravels after crossing paths with the gang, became a fan favourite for his increasingly desperate and unglamorous appearances. In this moment he eats a lemon, and the small, sour gag has lived on as a shareable reaction clip among fans, who reuse it whenever a scene needs a visceral, funny response to something unpleasant.