Unlike the other aliens, Ben acquired Benwolf in a unique way. In their visit to an old friend, Ben and the gang encounter a giant beast that resembles that of a werewolf. It was thought of as a Yenaldooshi (Navajo for Skinwalker) at first, but after its strange intentions of collecting technological scrap made them realize that it was no ordinary wolfman. Ben, as Wildvine, fights it, but as he transforms back to Ben, the alien wolf comes after him and attacks his wrist, scratching his Omnitrix. The Omnitrix reacts, letting out a strange, yellowish glow. From there on, Ben goes through a strange transformation process, that is, until the DNA from the alien wolf is fully merged with the device, thus granting Ben the alien, Benwolf.

Benwolf is a Loboan from the moon of Anur Transyl, Luna Lobo.