Altair's Static Shield

A shield made purely from sparking lightning appears on your arm. For the duration, it counts as a shield with which you are proficient. When you are hit with a melee attack, lightning springs forth from the shield hitting creatures within 5 feet of you. The creatures take 2d6 lightning damage.

At higher levels: When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each spell slot above 4th.