"Back with a Vengeance" is the 13th and final episode of the second season of , originally airing on October 9, 2006. The episode is a critical milestone in the series, featuring the first alliance between Ben's primary antagonists, Vilgax and Kevin 11 , and the introduction of the Omnitrix's powerful "Master Control". Plot Summary
Ben's initial arrogance with the Master Control leads to near-disaster, forcing him to acknowledge his overconfidence by the episode's end. Production Details Ben 10 S02:E13 - Back With a Vengeance - Tubi
This episode is the first time Ben accesses the watch's full potential. He later resets it, reverting the device to its standard random activation and timeout functions.
Both Vilgax and Kevin are banished to the Null Void, where they remain trapped until later seasons of the franchise.