Ben 10

S03:E05 - Benwolf

In New Mexico, Max stops to visit an old friend who's a Navajo Chief. Suddenly a powerful storm comes out of nowhere, and behind bolts of purple lightning a NAVAJO WEREWOLF appears. As Ben battles the werewolf, he appears to be bitten and turns into Benwolf. But it turns out the werewolf is actually an alien, and Ben sampled its DNA. In the end, Ben reverts back to his normal self, and stops the werewolf's plan to assemble a high tech satellite device for some unknown nefarious purpose.