Kabonger

Rare Greatclub (Requires Attunement by a Bard)

This item functions as a guitar for the one attuned to it. When you use it as a spellcasting focus, your spell save DC and spell attack modifier increase by one. While you are attuned to it, you can use it as a magical +1 weapon.

The first time a creature is hit by the item, it suffers the effects of a Thunderous Smite.