Tanazir Quandrix is a mythic Legendary Creature — Elder Dragon card from Strixhaven: School of Mages (STX), collector number 240. Current market price: $0.69 (foil $1.65), TCGplayer market prices via Scryfall.
Flying, trample When Tanazir Quandrix enters, double the number of +1/+1 counters on target creature you control. Whenever Tanazir Quandrix attacks, you may have the base power and toughness of other creatures you control become equal to Tanazir Quandrix's power and toughness until end of turn.