Ben 10: Omniverse S01 E10 Of Predators and Prey (2)

"Two Bens are better than one."

While trapped in Khyber's ship, Khyber tells Ben that he needs different alien DNA to complete the evil incomplete version of the Omnitrix the Nemetrix. He also reveals that Dr.Psychobos assigned him to hunt down various species for DNA to transfer it to the Nemetrix.