Nirnaeth Arnoediad

If Nirnaeth Arnoediad would enter the
battlefield, sacrifice a Swamp instead. If you
do, put Nirnaeth Arnoediad onto the
battlefield. If you don't, put it into its
owner's graveyard.
{t}: Add {b} to your mana pool.
{t}, Sacrifice a Swamp: Add {b}{b}{b}{b} to
your mana pool.