Is Rotten Reunion legal in Standard, Modern, and Commander?

Rotten Reunion is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Pauper, Historic.

Rotten Reunion

Q: What type of card is Rotten Reunion?

Rotten Reunion is an Instant. Its oracle text reads: "Exile up to one target card from a graveyard. Create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.) Flashback {1}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.) *Aunt and Uncle Greyfeld loved dinner guests.*"

Instant

Exile up to one target card from a graveyard. Create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)