Stormbringer

While concentrating on spells, you create a crackling aura of stormy energy. If you are concentrating on a spell and are hit by a melee attack, your attacker must succeed on a dexterity saving throw or by struck by a lightning bolt dealing 1d6 lightning damage. This only occurs if you succeed on your concentration save.

If you fail your concentration save, the spell collapses, and the residual energy deals 1d6 lightning damage to anyone, friend or foe, within 10 feet.