Is Boneyard Lurker legal in Standard, Modern, and Commander?

Boneyard Lurker is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Boneyard Lurker

Q: What type of card is Boneyard Lurker?

Boneyard Lurker is a Creature — Nightmare Beast. Its oracle text reads: "Mutate {2}{B/G}{B/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.) Whenever this creature mutates, return target permanent card from your graveyard to your hand."

Creature — Nightmare Beast

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.)