A-me-oba

When A-me-oba enters the battlefield, you may have it become a copy of target creature, except it is a black and green Fungus in addition to its other colors and types, and gains Decompose 2
(To decompose, put 2 -1/-1 counters on target creature. Then, put 2 1/1 black and green Fungus creature tokens with trample onto the battlefield under your control).
It ate it all so it could emulate anyone, anytime, anywhere.