Dragonfire

You roar, transforming your head into a dragon's and unleashing fiery breath. Each creature in a 30-foot cone must make a Dexterity saving throw. A target takes 4d6 fire damage on a failed save, or half as much on a successful one.
The fire spreads around corners. It ignites flammable objects in the area that aren't being worn or carried.
At Higher Levels.
When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d6 for each slot level above 2nd.