Velvet,the Revenge Artist

{2}{u}{g} Mutate(If you cast this spell for its
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.)
Trample
Whenever this creature mutates, it gets +X/+X
until end of turn, where x is equal to the number
of times its mutated.
If this card does combat damage
to a player put X +1/+1 counters on it.