Volt Charged Blade

You brandish the weapon used in the spell’s casting, infusing it with elemental lightning, and make a melee attack with it against one creature within 5 feet of you. On a hit, the target suffers the weapon attack’s normal effects, and becomes Negatively Charged until the start of your next turn. If you're hit by an attack with a reach of 5ft, or a spell with the range of 'touch' by a creature that is Negatively Charged, you may shock the attacker with lightning damage equal to your spellcasting ability modifier, after which the creature is no longer Negatively Charged. This additional damage can only be triggered once per casting, and multiple instances of this feature cannot stack.

This spell’s damage increases when you reach certain levels. At 5th level, the melee attack deals an extra 1d8 lightning damage to the target on a hit, and the lightning damage to the attacking creature increases to 1d8 + your spellcasting ability modifier. Both damage rolls increase by 1d8 at 11th level (2d8 and 2d8) and 17th level (3d8 and 3d8).