Gorgon Hydra of Death

Trample, lifelink
Whenever you gain a life, put that many +1/+1
counter on Gorgon Hydra of Death.
{1}{w}, remove a +1/+1 counter and pay 1 life:
Exile a nonland permanent in play with a stone counter on it until it's owner may pay 2 life
anytime to return it to the battlefield.
Planeswalkers exile with the ability, entered the battlefield with one less loyalty counter.