Devouring Inferno

Flames explode from a creature you can see within range. The target must make a Dexterity saving throw, taking 10d6 fire damage on a failed save, or half as much on a success. Regardless of the outcome, the target becomes wreathed in flames.

Any creature within 5 feet of a creature wreathed in flames that isn’t immune to fire must make a Dexterity saving throw at the start or end of its turn. On a failed save, it takes 8d8 fire damage and becomes wreathed in flames as well.

A creature wreathed in flames must make a Dexterity saving throw at the end of each of its turns. On a failure, it takes 5d6 fire damage. On a success, the flames are extinguished.