The line comes from Fallout 2, released in 1998, where Frank Horrigan appears as the Enclave's hulking super mutant enforcer and the game's final antagonist. His short Semper Fi delivery became a favourite among Fallout fans, who clipped it for forums, videos and soundboards as shorthand for brute military menace. It has stayed in circulation because Horrigan remains one of the series' most memorable villains, and the two-word phrase is instantly recognisable even to players who have not finished the game.