Witch Storm

You conjure an erratic cloud of dust and static in a 10-foot-tall, 30-foot-radius Cylinder that floats above you at a point you choose within range for the duration.

When you cast the spell and once on each of your subsequent turns as a bonus action, you can cause jagged bolts of lightning to descend from the cloud. Each other creature beneath the cloud must make a Dexterity saving throw, taking 2d12 Lightning damage on a failed save or half as much damage on a successful one.

This spell ends early if you use your bonus action on a subsequent round for anything else. When it ends, each other creature within range that can see the cloud must succeed on a Constitution saving throw or have the Blinded condition until the end of your next turn.

Using a Higher-Level Spell Slot. The damage increases by 1d12 for each spell slot level above 2.