The term "Chaos Bakugan" is a name given to any Bakugan that has been corrupted and mutated by Chaos, or born from it. While a massive army of these creatures served Mag Mel and Razenoid in Bakugan: Mechtanium Surge and were thought to be extinct after the two villains were defeated by the Battle Brawlers, they reappear more powerful than ever before in Bakugan: Battle Dimensions.