When this creature specializes, create a token that's a copy of a creature card exiled with this creature, except it's 3/3 and has flying and haste. Sacrifice it at the beginning of your next end step.

Flying
Acid Breath — When this creature enters, target creature an opponent controls gets -3/-3 until end of turn.

Affinity for tokens (This spell costs less to cast for each token you control.)
Whenever a token you control enters, tap target nonland permanent an opponent controls. It doesn't untap during its controller's next untap step.

When this creature specializes, create a token that's a copy of a creature card exiled with this creature, except it's 5/5 and has trample and haste. Sacrifice it at the beginning of your next end step.

When this creature specializes, create a token that's a copy of a creature card exiled with this creature, except it has double strike and haste. Sacrifice it at the beginning of your next end step.

When this creature specializes, create a token that's a copy of a creature card exiled with this creature, except it's 4/4 and has menace and haste. Sacrifice it at the beginning of your next end step.

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.)
Whenever this creature mutates, tap up to X target creatures, where X is the number of times this creature has mutated. Those creatures don't untap during their controller's next untap step.