Touhou Project is a long-running Japanese bullet hell game series created by ZUN, where players dodge dense patterns of projectiles while launching their own attacks. Charging sounds like this one are a natural part of that gameplay, marking the moment a character gathers power before firing. As clips from the series circulated in fan videos, streams and memes, the effect became a handy shorthand for rising power outside the games themselves. Creators now use it to add game-like tension to edits, even when the video has nothing to do with Touhou.