Eldritch storm

A swirling dark cloud of ashes fills a 40-foot-radius 100-foot-tall Cylinder centered on a point within range. The cloud’s area is Heavily Obscured. It lasts for the duration or until a strong wind (like that created by Gust of Wind cast with a 5th level spell slot) disperses it.

When the cloud appears, each creature in it makes a Constitution saving throw, taking 10d8 Necrotic damage on a failed save or half as much damage on a successful one. A creature must also make this save when the Cylinder moves into its space and when it enters the Cylinder or ends its turn there. A creature makes this save only once per turn.While a creature is within the Cylinder, it has the Blinded condition.

The cloud occasionally flashes with purple lightning. As a bonus action, you can cause the lightning to strike a creature within the cylinder.Target a creature you can see under the cloud. A bolt of purple lightning shoots from the cloud to that creature. The target makes a Dexterity saving throw, taking 4d10 Force damage on a failed save or half as much damage on a successful one.

The cloud moves 10 feet away from you in a direction you choose at the start of each of your turns.

When the storm appears or when it creates lightning, any creature that is aware of the storm and within 150 of the storm must succeed on a Wisdom saving throw or drop whatever it is holding and have the Frightened condition for 1 minute.