Anden's Annihilating Arc

A web of electrical energy surrounds your body, surging outward and detonating in a sphere around you. Each creature within 30 feet of you must make a Dexterity saving throw. A creature takes 8d6 lightning damage on a failed save or half as much on a successful one. Additionally, each target within 10 feet of a creature that failed their Initial saving throw must make a Dexterity saving throw, taking 4d4 lightning damage on a failed save or half as much on a successful one. A creature can only suffer this additional damage once per casting.

The caster is immune to any damage from this spell but gains a level of Exhaustion.