Thrasta, Tempest's Roar is a mythic Legendary Creature — Dinosaur card from Magic Online Promos (PRM), collector number 91299.
This spell costs {3} less to cast for each other spell cast this turn. Trample, haste Trample over planeswalkers (This creature can deal excess combat damage to the controller of the planeswalker it's attacking.) Thrasta has hexproof as long as it entered this turn.