Uriel, Hellguard Lieutenant

Flying, Unbridled furry (Whenever this creature attacks, it gets +1/+0 until end of turn for each vengeance counter you have.)
Whenever one or more of your creatures are destroyed you may reveal this card from anywhere if you do you gain a vengeance counter.
When Uriel, Hellguard Lieutenant enters the battlefield and you have 10 or more vengeance counters transform.