Mesmeric Fiend is a common Creature — Nightmare Horror card from Torment (TOR), collector number 69. Current market price: $1.50 (foil $48.99), TCGplayer market prices via Scryfall.
When this creature enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card. When this creature leaves the battlefield, return the exiled card to its owner's hand.