Akali, the Rogue Assassin

Flash, Shroud
Assassin's Mark - Whenever you cast a noncreature spell, you may put an assassination counter on target creature you don't control.
{2}{u}{b}{r}, {t} - Destroy target creature with an assassination counter on it. You may search your library for a card with converted mana cost lesser than or equal to the destroyed creature and put it into your hand. Shuffle your library.