I had the dog and Vilkas in my house when I was storing my items, and I accidentally made Vilkas attack the dog. The dog won 3 out of 3 battles, Vilkas always ended up on the floor. Finally Vilkas ran to my table where all my weapons are, and grabbed a random staff and orc axe, he went after the dog again. The dog ran out the door and Vilkas chased him shooting icicles. I couldn't quit laughing, but I wish I could have canceled that action..