Trevon's Storm Sphere

9-level Conjuration

You create a 120 foot-radius sphere of cloud centered on a point within range. The cloud spreads around corners, and its area is heavily obscured. It lasts for the duration unless dispelled. When the spell is cast a large lightning burst goes through the cloud and any creature in it must make a dexterity saving through. On a failed save the creature takes 10d6 Lightning Damage and 10d6 Thunder Damage, or half as much on a successful save. While you are in the cloud, you can sense everything in the cloud as if you had blindsight, but can't see out of the cloud. You also have advantage on any attack roll against any creature also inside the cloud. During your turn you can choose to make an attack. As an action, you can choose to do a lightning attack or thunder attack. If you choose a lightning attack, make a ranged spell attack against a creature. On a hit, an arc of lightning strikes the creature and they take 6d6 lightning damage. If you choose a thunder attack, a loud boom echos from a point you choose in the cloud, any creature within 5 feet of the point must make a constitution saving throw, on a fail, the creature takes 3d6 thunder damage and is deafened until the start of your next turn, on a success, the creature takes half damage, and isn't deafened. At the end of your turn, choose a damage type, lightning or thunder. Until the start of your next turn, every creature that starts its turn within the cloud or enters the cloud for the first time in its turn must make a dexterity saving throw if the damage is lightning, or a constitution saving throw if the damage is thunder. On a failed save the creature takes 2d8 damage of the type chosen, or half as much on a failed save