Sly Spy 
Creature — Human Spy
Whenever this creature deals combat damage to a player, that player reveals the top card of their library. Put that card into your hand and you lose life equal to its mana value.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyNOT LEGALvintageNOT LEGALcommanderNOT LEGAL