Fear of Impostors is a uncommon Enchantment Creature — Nightmare card from Duskmourn: House of Horror (DSK), collector number 57. Current market price: $0.29 (foil $0.34), TCGplayer market prices via Scryfall.
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.)