Darvin's Infernal Storm

The air in a 100-foot-radius sphere centered on yourself ignites in a mixture of flames and lightning and continues burning and discharging violently for the duration. A creature that starts it's turn inside the area or enters the area for the first time must make a Dexterity saving throw. The sphere spreads around corners. A creature takes 20d6 fire damage and 20d6 lightning damage on a failed save, or half as much damage on a successful one. The affected area is considered difficult terrain.

The spell damages objects in the area and ignites flammable objects that aren't being worn or carried.