Thunderbuss

This magic ranged weapon is a flared pistol with the storm rune engraved along the barrel. You gain a +1 bonus to attack and damage rolls made with it. It requires no ammunition, its damage is thunder instead of piercing, and it doesn't have the loading property.

Invoking the Rune: As a bonus action, you can invoke the weapon's rune to launch a ball of energy to a point you can see within 30 feet of yourself. The energy then detonates into a 10-foot-radius sphere of turbulent wind and thunder centered on that point, and each creature in that sphere must make a DC 14 Constitution saving throw. On a failed save, a creature takes 3d6 thunder damage, and it can't take reactions until the end of your next turn. On a successful save, a creature takes half as much damage only.

Once the rune has been invoked, it can't be invoked again until the next dawn.