Tyrranax Rex is a mythic Creature — Phyrexian Dinosaur card from Phyrexia: All Will Be One Promos (PONE), collector number 189p. Current market price: $7.91 (foil $10.71), TCGplayer market prices via Scryfall.
This spell can't be countered. Trample, ward {4}, haste Toxic 4 (Players dealt combat damage by this creature also get four poison counters.)