Artemis, Goddess of the Hunt

As an additional cost to cast this spell, sacrifice a creature.
Haste, First Strike, Reach, Deathless (If this card
would be put into a graveyard, exile it instead. It can
be played from exile for its mana cost.)
{4}{g}{g}, {t}: Artemis, Goddess of the Hunt deals
damage equal to her power to target creature or
opponent.