Luigi is Mario's younger brother in Nintendo's long-running Mario games, usually portrayed as taller, more nervous and far more easily scared than Mario. That contrast is why a panicked Luigi shout became popular in fan edits and in the SMG4 machinima community, where game characters are reused for comedy sketches. Short voice clips like this spread through soundboards and short videos because they are instantly recognisable, easy to download as an MP3 and work even without the original scene, making them a staple reaction sound for gaming creators.