Yeti is also "Wendigo" in the Marvel Comics. He's a bad guy but he's not. I don't know how you're supposed to understand it. They'll make any villain a hero and then a villain again. Who? What? Everyone's a fricking coin. Toss us in the air, where will we land?! Oh, today I'm going to smash Wolverine's face. Tomorrow I'm pals with Storm. We're stopping Magneto together. Isn't this grand? Oh wait, so sorry, I've decided to betray you all by smashing Professor X's face. Tomorrow you'll do the same. It's all just madness madness madness.
Screenshots nabbed from here
