Beledros Witherbloom is a mythic Legendary Creature — Elder Dragon card from Strixhaven: School of Mages (STX), collector number 163. Current market price: $3.59 (foil $10.40), TCGplayer market prices via Scryfall.
Flying At the beginning of each upkeep, create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life." Pay 10 life: Untap all lands you control. Activate only once each turn.