Luigi is Mario’s younger brother and a long-running Nintendo character, recognised for his nervous, high-pitched voice and easily startled personality. This short exclamation has circulated widely as a reaction sound on soundboards, short-form video and gaming edits, where creators reuse it far beyond any single game. Its appeal comes from how instantly readable it is: one surprised voice tells viewers exactly how to feel about a clip. Because the reaction fits fails, reveals and unexpected moments alike, it has remained a handy shorthand for comic shock.