Treasure Thief

Espionage {2} (You may pay an additional {2} as
you cast this spell. If you do, it enters the battlefield under an opponent's control.)
When Treasure Thief enters the battlefield, if
you don't own it, its owner chooses an artifact or creature you control and gains control of it.
When Treasure Thief enters the battlefield, if
you own it, gain control of all permanents you
own.