Amaya, Stealer of Breath

Ninjutsu {u}{b}, Discard a card ({u}{b}, Discard a card, return an unblocked attacker you control to
hand: Put this card onto the battlefield from your
hand tapped and attacking.)
Whenever Amaya, Stealer of Breath deals
combat damage to a player, that player reveals
the top card of their library. If it's a creature card, that player discards it.