Luigi is Mario's younger brother in Nintendo's Mario franchise, known for his higher, more nervous voice compared to Mario. Short voice lines like his bye bye greeting and farewell have been lifted from the games and shared as isolated clips on soundboards and in video edits. The clip spread because it is instantly recognisable, needs no context, and works for any departure. It remains popular with gaming creators who want a familiar, family friendly way to mark an exit, a loss, or a comedic ending.