The level up jingle comes from the Pokemon video games, where it plays when a Pokemon gains enough experience to reach a new level. As Pokemon gameplay, streams and fan edits spread online, the short tune became shorthand far beyond the games themselves, recognised even by viewers who had never played them. Creators now use it to signal growth, success or a new stage in almost any kind of video, from gaming clips to fitness progress and study milestones. Its staying power comes from that instant association: a few notes are enough to say someone has levelled up.