Wilderness Fox

Mutate {1}{w} (If you cast this spell for it's mutate
cost, put it over or under target non-human creature
you own. They mutate into the creature on top plus all abilities from under it.)
Vigilance
Whenever this creature mutates, put a transformation counter on it. Then, if it has 3 or
more transformation counters on it, sacrifice it,
then you may put a card called The Abomination
from outside the game onto the battlefield.