Helmuth, the Unending

Haste, Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)
Sacrifice Helmuth, the Unending: Deal X Damage
to any target, where is is Helmuth, the Unending's power.
Whenever a creature enters the battlefield from your
graveyard, return Helmuth, the Unending from
your graveyard to the battlefield.