Koraki, the Crowmaster

Shroud
When Koraki enters the battlefield, create a 1/1
Crow for each artifact your opponents control.
{t}, Tap an untapped Crow you control: Koraki
deals 1 damage to target creature an opponent
controls. That creature can't block this turn.
{u}{b}, {t}, Sacrifice {x} Crows: Gain control of
target artifact an opponent controls with
converted mana cost {x}.