Karai, Future of the Foot (TMT)

Sneak 2WB (You may cast this spell for 2WB if you also return an unblocked attacker you control to hand during the declare blockers step. She enters tapped and attacking.)
Whenever Karai deals combat damage to a player, return target creature card from your graveyard to your hand. If her sneak cost was paid this turn, instead return that card to the battlefield.