Vaal Hazak

Flying
X and * are equal to the amount of creature
cards in your graveyard.
{b}{b}{b}: Put target creature card in your
graveyard into play, it's power and toughness is
halved, then rounded up. That creature is now a
black corpse in addition to its other types and it
has "When this creature dies, exile it instead." If
the card had a converted mana cost of {5} or
greater, this ability cost {b}{b} more.