Vysoren's Energy Blast

A brilliant blast of energy flashes in a 60-foot radius centered on a point you choose within range. Each creature in that light must make a Dexterity saving throw. On a failed save, a creature takes 20d10 damage of your choice (acid, cold, fire, force, lightning, narcotic, poison, or thunder) and is knocked prone. On a successful save, it takes half as much damage and isn't knocked prone by this spell. Undead and oozes have disadvantage on this saving throw.