Tidebinder Mage

If another player gains control of Tidebinder Mage, the creature will no longer be affected by the ability preventing it from untapping, even if you later regain control of Tidebinder Mage.

If you lose control of Tidebinder Mage between when it entered the battlefield and when the ability resolves, the target creature will become tapped. However, it won’t be affected by the other effect and will untap as normal during its controller’s untap step.

If you gain control of the creature that’s being prevented from untapping, that creature won’t untap during your untap step for as long as you control Tidebinder Mage.