Astonishing Breath Weapon

Your deepened connection to your draconic ancestor has made your breath weapon more powerful. You gain the following benefits:

• Increase your Constitution score by 1, to a maximum of 20.
• Your breath weapon is a bonus action instead of a normal action.
• If you use your breath weapon on one or more creatures immune to its damage type, they make a Constitution saving throw equal to your breath weapon's save DC, losing their immunity to that damage type a number of rounds equal to your constitution modifer on a failed save.