Herkarion, PureSteel Incarnate

If Herkarion, PureSteel Incarnate is not in your Library or on the Battlefield, shuffle it into your Library immediatly. Then, return to your hand Steel Gargoyle, Steel Immortal and PureSteel Monolith from your Graveyard and/or Exile.
Indestructible, Menace.
When Herkarion attacks, gain permanent control of all Artifacts defending player controls.
{x}, sacrifice X Artifacts: Herkarion gains +X/+X and Anihilator X until end of turn.