Ojutai, Soul of Winter is a rare Legendary Creature — Dragon card from Fate Reforged (FRF), collector number 156. Current market price: $0.44 (foil $12.90), TCGplayer market prices via Scryfall.
Flying, vigilance Whenever a Dragon you control attacks, tap target nonland permanent an opponent controls. That permanent doesn't untap during its controller's next untap step.