Wildfire Eternal 
Creature — Zombie Jackal Cleric
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.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL