Relinquished

Relinquished can't be cast from your hand or library except by the ability activation of Black Illusion Ritual.
{t}: Take control of target creature and tap it. It doesn't untap during your untap step. Relinquished's base power and toughness each become that of the tapped creature. If Relinquished would be removed from the battlefield, instead, exile the tapped creature.
Only one creature can be controlled by this ability at a time.