Blue-lightning Blade

You brandish the weapon used in the spell’s casting as a bonus action when you hit a creature with a melee attack. Blue lighting consumes your blade dealing 1d6 lighting damage to the creature hit. On the creatures turn blue lightning can be seen surrounding the creature. It has to make a Dex DC save equal to the spell casters spell save DC. If it fails it takes an additional 1d4.

This spell’s damage increases when you reach certain levels. At 5th level, the melee attack deals an extra 1d6 lightning damage to the target on a hit, and the lightning damage on the creature’s turn increases to 1d4. Both damage rolls increase 1d6 and 1d4 respectfully at 11th level (total 3d6 and 3d4) and 17th level (total 4d6 and 4d4)