Grorian Hydra

When Grorian Hydra enters the battlefield, create X 0/* head tokens with "When this token is destroyed, create two copies of it at the upkeep of your next turn" and "This creature's toughness is equal to the number of heads you control."
Grorian Hydra's power is equal to the number of heads you control. And it's toughness is equal to twice the number of heads you control
Enrage - Whenever Grorian Hydra takes damage, destroy a head token for each damage it took