Is Souvenir Snatcher legal in Standard, Modern, and Commander?

Souvenir Snatcher is legal in: Legacy, Vintage, Commander.

Souvenir Snatcher

Q: What type of card is Souvenir Snatcher?

Souvenir Snatcher is a Creature — Bird. Its oracle text reads: "Mutate {5}{U} (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.) Flying Whenever this creature mutates, gain control of target noncreature artifact."

Creature — Bird

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.)