Ben 10 season 2 episode 12 : Dr. Animo and the Mutant Ray

When Ben tries to take apart the Omnitrix to see how it works, he ends up breaking off its face and causing weird combinations of his alien forms when he transforms. Additionally, the broken piece begins mutating the smaller creatures it comes into contact with. Meanwhile, Dr. Animo escapes from prison and, during a battle with Ben, finds the broken piece of the Omnitrix. Using it, he is able to complete his large-scale Transmodulator, giving him the power to mutate the entire planet in a single shot.