Sunkept Crypt

As Sunkept Crypt enters the battlefield, you may exile target Zombie creature card from your graveyard or exile target creature card with embalm or eternalize from your graveyard. If you don't, Sunkept Crypt enters the battlefield tapped.
{t}: Add {w}, {u}, or {b} to your mana pool.
Even the dead are made useful in the hands of Bolas.