Dragons wrath

You summon one or more ancient, spectral dragon skulls into the air. Each skull locks onto a target location, then unleashes a brilliant beam of compressed force energy. The beam detonates on impact in a concussive, soundless explosion. Each creature in a 20-foot-radius Sphere centered on that point makes a Dexterity saving throw, taking 8d6 Force damage on a failed save or half as much damage on a successful one.

Using a Higher-Level Spell Slot. The damage increases by 1d6 for each spell slot level above 3.