Crimson Crisis

During the casting of this spell, you must concentrate. If you take damage, it does not interrupt the casting, rather you must make a concentration check, halting casting on a failure.

At the completion of this spell, the area in a 500 ft. sphere becomes enclosed in a huge purplish red dome that extends underground, and the top of the dome fills with crimson clouds. These clouds then open up like an eye, and blast everything in the dome of the casters choice that is open to the sky with red lightning. Creatures struck must make a Dex save, taking 3d12 lightning damage and 3d12 necrotic damage on a failed save, or half as much on a success. The caster may repeat the lighting strikes as a bonus action on its turn, except the turn the spell was cast.