Is Glowstone Recluse legal in Standard, Modern, and Commander?

Glowstone Recluse is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Glowstone Recluse

Q: What type of card is Glowstone Recluse?

Glowstone Recluse is a Creature — Spider. Its oracle text reads: "Mutate {3}{G} (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.) Reach Whenever this creature mutates, put two +1/+1 counters on it."

Creature — Spider

$0.13 ↗6 similarCommander, Modern

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.)