Damien, Scourge of Eldin

When Damien, Scourge of Eldin or another
creature you control deals combat damage to a
player or planeswalker, you may sacrifice it. If
you do, your opponent reveals their hand. You
may choose a nonland card with converted mana
cost equal to the sacrificed creature's converted
mana cost. You may cast that spell this turn by
exiling a card from your graveyard instead of
paying that spell's mana cost.