Eye of Sauron

When Eye of Sauron enters the battlefield choose target permanent an opponent controls. Then, that card becomes the ring bearer unless there is already a ring bearer on the battlefield. (There may be only one ring bearer in the battlefield at a time) If the ring bearer taps, attacks, blocks, uses an ability, or leaves the battlefield; exile Eye of Sauron, then return it to the battlefield transformed under it's owner's control.