Maw Abyss

Maw Abyss enters the battlefield tapped.
When Maw Abyss enters the battlefield, exile a creature card from your graveyard.
{t}: Add {b} to your mana pool.
{2}{b},{t}, Sacrifice a creature: Return target
creature card exiled with Maw Abyss to the battlefield under your control. Activate this
ability only when you could cast a sorcery or
instant.