Eldritch Annihilation

You gather eldritch energy in your body to produce a ball of pure energy while chanting. You cannot move while gathering the energy. Once 2 turns have passed, you may choose a point within 120ft to send the ball. Once a ball reaches its destination or impacts against a solid surface, the ball explodes. Each creature within 15 feet of the point where the ball explodes must make a Dexterity saving throw. A creature takes 5d10 necrotic damage on a failed save, or half as much damage on a successful one, plus 2d8 force damage.

You stop casting the spell if you are incapacitated, interrupted, move by choice, or can no longer speak.