The sound comes from the Doom video game series, whose modern soundtracks are famous for aggressive, guitar-driven metal that matches the game's fast, brutal combat. Online, the phrase when Doom music kicks in became shorthand for the moment a situation suddenly turns serious, and creators began cutting the riff into videos of workouts, gaming highlights, comebacks and everyday confrontations. Its popularity has lasted because the shift is instantly recognisable, even to viewers who have never played the game, and it signals intensity without needing any explanation.