Vorunk, Undead Wanderer

Vorunk, Undead Wanderer enters the battlefield tapped.
{g}{g}{t} Discard a card: Return target card from your graveyard to your hand.
{b}{b}{t} Sacrifice a creature: Destroy target creature, It can't be regenerated.
Vorunk, Undead Wanderer's power is equal to the number of zombies in all graveyards.