Escuarsh, Swapper of Souls

Lifelink, Deathtouch
Escuarsh has Player as long as you don't control any other creatures and if you do, she cannot leave the battlefield unless she dies or gets exiled and cannot enter the battlefield after she leaves.
Whenever Escuarsh leaves the battlefield, target creature you control gains all of Escuarsh's abilities and becomes a blue and black wizard in addition to it's other colors and types.
Mana Pool - {u} or {b}