Conflagration

You ignite a wildfire to scorch the battlefield, centered on one creature you can see within range. The target must succeed on a Dexterity saving throw or take 2d6 fire damage and burn uncontrollably. At the start of each of its turns, the target must make another Dexterity saving throw. On a failed save, it takes 1d6 fire damage. A successful saving throw ends the spell.

While the spell is active, if the target takes fire damage from any source other than this spell, each creature in a 15- foot-radius sphere centered on the target must make a Dexterity saving throw. A creature takes 1d6 fire damage on a failed save, or half as much damage on a successful one. The fire spreads around corners. It ignites flammable objects in the area that aren’t being worn or carried. This effect can only occur once per round.

At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, all damage rolls increase by 1d6 for each slot level above 3rd.