I saw this game on mmohut a while back i'm almost 100% sure of it. Anyways in this game when you created your character you got to pick a certain hero/champion of some sort that you could transform into a any time within the game. While transformed you got buffed stats and new abilities but once your transformation was over you'd not be able to transform again for 30 min.

It was really unique and i'm almost certain that Remotay did a video on it but i just cannot remember the name of the game! Someone please help me out here!