Dragonfire Breath

You inhale deeply and exhale a blast of superheated flame energy. Choose a 15-foot cone or a 30-foot long, 5-foot wide line. The chosen area emanates from the caster's mouth. Creatures in the area of effect must make a dexterity saving throw. On failure, they suffer 1d8 fire damage. On failure they take half as much. Unattended flammable objects in the area do not automatically ignite, but a repeated application of the spell will cause them to start burning.

Cantrip Upgrade. The damage increases by 1d8 when you reach levels 3 (2d8), 5 (3d8), and 11 (4d8), and 17 (5d8).