Inverse Hydra

Mutate {b}{g}
Inverse Hydra enters the battlefield with 4 -1/-1 counters on it.
Whenever this creature mutates, remove a -1/-1 counter from it. If it has no -1/-1 counters on it,
it gains trample, deathtouch, and double strike
until end of turn.
"It is evolving, just backwards."