Call of Duty: Black Ops 3 was released in 2015, and its multiplayer progression system rewarded players with a short musical sting each time they gained a rank. The sound became familiar to millions of players who spent hours in online matches, and clips of it soon circulated beyond the game itself. Editors now reuse it as shorthand for levelling up, even in videos that have nothing to do with Call of Duty, because the bright, victorious tone is instantly recognisable as a moment of achievement.