Grave Corrupter

Trample, deathtouch
Grave Corrupter's power is equal to the number of Swamps in your graveyard.
At the beginning of your upkeep, if there are more than 5 Swamps in your graveyard, you may return target land from your graveyard to your hand.
Creatures your opponents control get -1/-0 for each non-Swamp land in your graveyard.
Even the dead aren't safe.