Dralgoth the Nightstalker

Whenever Dralgoth the Nighstalker attacks, choose a card type, then exile all cards from defending player's graveyard. Create X 1/1 black horror creature tokens and that player puts the top X cards of his or her library into his or her graveyard, where X is the number of cards of the chosen type exiled this way.
Sacrifice three permanents: Target land becomes a swamp.