Deathkiller Assassin

Flying, skulk, hexproof
Whenever Deathkiller Assassin attacks and isn't blocked,
Deathkiller Assassin gets +2/+0 until end of turn.
Whenever Deathkiller Assassin deals combat
damage to a player, return target card from your
graveyard to your hand, and you may play a card from
your hand without paying its mana cost.
Murder and necromancy, the perfect combination.