The Arkenstone of Thráin

If a creature an opponent controls would die,
exile it instead.
{2}, {t}, Sacrifice Stone of Erech: Exile target
player's graveyard. Draw a card.
"The Heart of the Mountain; and it is also the heart
of Thorin. He values it above a river of gold.
I give it to you. It will aid you in your bargaining."