Ben enlists Kevin’s help to break the Omnitrix’s physical seal. The experiment backfires spectacularly:

Instead of unlocking Master Control, the Omnitrix resets, and several of Ben’s alien forms (including Chromastone, Goop, Way Big, and Spider-Monkey) are physically ejected from the watch as independent, mindless entities.

This wasn't the cyborg Vilgax of the past; this was a "Conqueror of Ten Worlds" with a vast array of powers, including flight, super strength, and wind breath, making him a more versatile threat than ever before.