Leyline Tyrant is a mythic Creature — Dragon card from Zendikar Rising (ZNR), collector number 348. Current market price: $6.85 (foil $5.88), TCGplayer market prices via Scryfall.
Flying You don't lose unspent red mana as steps and phases end. When this creature dies, you may pay any amount of {R}. When you do, it deals that much damage to any target.