The line comes from Disney's The Emperor's New Groove (2000), where the arrogant Emperor Kuzco, voiced by David Spade, punctuates his schemes with the catchphrase 'Boom, baby!'. Fans clipped the quote early on, and it spread through reaction videos, gaming montages and meme edits as a shorthand for a flawless victory. It sits comfortably alongside impact sounds like the vine boom, and its staying power comes from Kuzco himself: few cartoon characters deliver smug confidence as quotably as he does.