Lamented Root

Defender
As long as you have four or more Zombie
creature cards in your graveyard, Lamented Root gets +7/+0 and looses Defender.
Unearth {b}{b}{b}{b}: ({b}{b}{b}{b}: Return this card
from your graveyard to the battlefield. It gains haste.
Exile it at the beginning of the next end step or if it
would leave the battlefield. Unearth only as a sorcery.)