The phrase comes from a December 2008 Super Smash Bros Melee doubles match at Smashtastrophe 2, where SilentSpectre and Tang trapped Zhu in a relentless team combo. Commentators including HomeMadeWaffles shouted happy feet and then wombo combo as the hits kept landing, and a recording of the call was uploaded online soon after. It spread far beyond Smash as a universal reaction for any perfectly chained sequence, and gamers still quote it whenever a combo feels unstoppable.