If you're still playing you may have noticed they added campaign to the game in the form of vs. AI battles with a twist. Well, this week is Uterra week with a special souped up version of the original Oros mission for you to tackle. I don't actually know if the mission goes away when the week ends, and for some reason it appears at the top of the campaign list instead of the bottom so it's easy to miss if you aren't looking for it. Winning it nets you an Uterra Legendary Chest which is basically a Legendary Chest with all Uterra cards in it with the exception of one of the common slots being replaced by an Alternate Art version of an Uterra card, including an AA Oros which is (currently) exclusive to these chests.

So if you're still playing I'd crank this one out before it (possibly?) goes away.

That Oros card seems totally insane from back when I played.

@fredchuckdave: It's a solid card but doesn't see much play outside of lifegain decks.