Alhammarret, High Arbiter is a rare Legendary Creature — Sphinx card from Magic Origins (ORI), collector number 43. Current market price: $0.33 (foil $0.39), TCGplayer market prices via Scryfall.
Flying As Alhammarret enters, each opponent reveals their hand. You choose the name of a nonland card revealed this way. Your opponents can't cast spells with the chosen name (as long as this creature is on the battlefield).