Crashing Revel

Whenever Crashing Revel attacks, discard a card.
Unearth {r} ({r}: Return this card from your
graveyard to the battlefield. Exile it at the beginning
of the end step or if it would leave the battlefield.
Unearth only as a sorcery.)
Whenever Crashing Revel would be exiled from
the battlefield, you may pay {1}{r}. If you do, put
it into your graveyard instead.