Grinning Demon is a rare Creature — Demon card from Onslaught (ONS), collector number 153. Current market price: $5.81 (foil $38.00), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, you lose 2 life. Morph {2}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)