This sound comes from Undertale, the 2015 indie RPG created by Toby Fox. The game's battle system made small interface sounds memorable, and the flee sound became recognizable to players who know its combat menus and humorous tone. Online, it shows up in Undertale memes, pixel-art edits, and gaming compilations whenever a person or character decides not to fight. It still gets used because the clip is extremely short, easy to place on a cut, and instantly reads as a fast retreat to fans of the game.