Tekuthal, Inquiry Dominus is a mythic Legendary Creature — Phyrexian Horror card from Phyrexia: All Will Be One Promos (PONE), collector number 71p. Current market price: $5.25 (foil $10.40), TCGplayer market prices via Scryfall.
Flying If you would proliferate, proliferate twice instead. {1}{U/P}{U/P}, Remove three counters from among other artifacts, creatures, and planeswalkers you control: Put an indestructible counter on Tekuthal. ({U/P} can be paid with either {U} or 2 life.)