Miirym, Sentinel Wyrm is a rare Legendary Creature — Dragon Spirit card from Secret Lair Drop (SLD), collector number 2500. Current market price: $35.11 (foil $37.38), TCGplayer market prices via Scryfall.
Flying, ward {2} Whenever another nontoken Dragon you control enters, create a token that's a copy of it, except the token isn't legendary.