Dragonborn Elemental Weapon

You have honed your breath weapon for use in melee combat. You are granted the following ability:

Imbue Weapon: As a bonus action, you can expend your breath weapon to imbue your weapon with the elemental energy corresponding to your draconic ancestry, dealing an additional 1d6 of the corresponding damage type with each attack until the end of your next turn. You can't use your breath this way again until you complete a long rest. This die increases to a d8 at 6th level, a d10 at 11th level, and a d12 at 16th level.