Is Fear of Impostors legal in Standard, Modern, and Commander?

Fear of Impostors is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Fear of Impostors

Q: What type of card is Fear of Impostors?

Fear of Impostors is an Enchantment Creature — Nightmare. Its oracle text reads: "Flash When this creature enters, counter target spell. Its controller manifests dread. (That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard. If it's a creature card, it can be turned face up any time for its mana cost.)"

Enchantment Creature — Nightmare

Flash

When this creature enters, counter target spell. Its controller manifests dread. (That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard. If it's a creature card, it can be turned face up any time for its mana cost.)

Set Duskmourn: House of Horror

Rarity Uncommon

Mana Value 3

Artist David Szabo

Collector # 57

Scryfall Gatherer