When you take the Attack action on your turn, you can replace one of your attacks with an exhalation of magical energy in either a 15-foot Cone or a 30-foot Line that is 5 feet wide. Choose the shape each time. Each creature in the area makes a Dexterity saving throw (DC 8 + your Constitution modifier + your Proficiency Bonus). On a failed save, a creature takes 1d10 damage of the type determined by your Draconic Ancestry trait; on a successful save, it takes half as much damage. The damage increases to 2d10 at character level 5, 3d10 at level 11, and 4d10 at level 17. You can use this trait a number of times equal to your Proficiency Bonus, regaining all expended uses when you finish a Long Rest.