Is Snapdax, Apex of the Hunt legal in Standard, Modern, and Commander?

Snapdax, Apex of the Hunt is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Snapdax, Apex of the Hunt

Q: What type of card is Snapdax, Apex of the Hunt?

Snapdax, Apex of the Hunt is a Legendary Creature — Dinosaur Cat Nightmare. Its oracle text reads: "Mutate {2}{B/R}{W}{W} (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.) Double strike Whenever this creature mutates, it deals 4 damage to target creature or planeswalker an opponent controls and you gain 4 life."

Legendary Creature — Dinosaur Cat Nightmare

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.)