Granite Witness is a common Artifact Creature — Gargoyle Detective card from Murders at Karlov Manor (MKM), collector number 206. Current market price: $0.07 (foil $0.05), TCGplayer market prices via Scryfall.
Flying, vigilance Disguise {W/U}{W/U} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.) When this creature is turned face up, you may tap or untap target creature.