Enchanted explosion

A bright streak flashes from your pointing finger to a point you choose within range and then blossoms with a low roar into an explosion of elements. Each creature in a 60-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 2 times damage on a failed save, or half as much damage on a successful 

At Higher Levels. When you cast this spell you use all you spell slots and add a d20 to damage for all slots