Diddy Kong is Nintendo's small, cap-wearing monkey companion to Donkey Kong, and this cry comes from Mario Kart: Double Dash, the 2003 GameCube racing game where two characters shared one kart. In that game, being struck by a shell, banana, or other item triggers a short character reaction, and Diddy's high voice made his version especially memorable to players. It has since circulated in gameplay videos, reaction edits, and soundboards, where its brief, comical distress still works as shorthand for being knocked down at the worst moment.