You create a violent storm of lightning around you. While this spell is active, at the end of each of your turns, all creatures of your choice in a 20 foot radius around must make a Dexterity saving throw, taking 8d8 lightning damage on a failed save and half as much on a successful one. Creatures carrying metal weapons or wearing metal armor have disadvantage on the saving throw.

When you cast this spell using a spell slot of 8th or higher level, the damage increases by 1d8 for each slot level above 7th.