The Avengers: Earth's Mightiest Heroes: Season 2, Episode 8

2 - 8: The Ballad of Beta Ray Bill

While searching for the fire demon Surtur, Thor is attacked by a powerful creature known as Beta Ray Bill, and the unthinkable happens when Bill lifts Thor's hammer as the two battle. Thor must ally himself with this strange warrior to save Asgard before Surtur and his demon army burn it to the ground.