Devourer

Mutate {1}{b/g} (You may play this card for its Mutate
cost, and when you do, place it on over or under a
Creature card. The card on top has the abilities and effects of the card underneath.)
Bloodlust, Hunting Call {g}{g}
Sith Poison (When this card attacks or defends
against a card, place a -1/-1 counter and Tainted
counter on it. Cards with a Tainted counter lose White
as a color and become Black.)