Deathspore Cultivator

You may pay {b}{g} and exile four land
or creature cards from your graveyard instead of
paying this spell's mana cost.
Deathtouch, menace
Undergrowth—When Deathspore Cultivator
enters the battlefield, creatures your opponents
control get -X/-X until end of turn, where X is
the number of creature cards in your graveyard.