Oblivion King Abyss

{b}{b}: Regenerate Oblivion King Abyss
{2}{b}: Discard a card. Exile one card at random from an opponents hand.
{3}{b}{b}: Whenever you cast a black creature spell, target a creature in your graveyard. You may cast that card without paying its mana cost. Your opponents gain life equal to its converted mana cost.