Wildfire Eternal is a rare Creature — Zombie Jackal Cleric card from Hour of Devastation (HOU), collector number 109. Current market price: $0.26 (foil $0.27), TCGplayer market prices via Scryfall.
Afflict 4 (Whenever this creature becomes blocked, defending player loses 4 life.) Whenever this creature attacks and isn't blocked, you may cast an instant or sorcery spell from your hand without paying its mana cost.