Master in Stealth

Target creature can't be block this turn. When
that creature deals combat damage for the first
time this turn, look at the top card of the
opponent libeary and yours. Exile one of those
cards, for the rest of the game you can play that
card, you may use mana of any kind to cast that
card. Put the rest of the cards to its owners
graveyard.
I may let them see me.