Gadrak, the Crown-Scourge is a rare Legendary Creature — Dragon card from Core Set 2021 Promos (PM21), collector number 146s. Current market price: — (foil $1.69), TCGplayer market prices via Scryfall.
Flying Gadrak can't attack unless you control four or more artifacts. At the beginning of your end step, create a Treasure token for each nontoken creature that died this turn. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")