Tiferet, Faceted Jewel

{1}{u}{u}: Tiferet may become a copy of any creature on the battlefield, except it retains this ability.
{1}{b}{b}: Return up to one creature from your graveyard to the battlefield. Use this ability only once per turn. That creature is exiled at end of turn, and Tiferet becomes a copy of it, except it retains this ability.