Cheeseball

Arbouro yells "I cast Cheeseball!" And then begins doing the Kamehameha hand position. Then, a giant cheeseball begins forming from his hands, and while it's forming he says, in the same intonation as Kamehameha, "Jeeeeble, Schmeeeeble, *GIBBERISH*!!!!" As the cheeseball forms, it slowly gets hotter and hotter until it becomes a fiery explosion of processed cheese. Each creature in a 20-foot-radius Sphere centered on that point makes a Dexterity saving throw, taking 8d6 Fire damage on a failed save or 4d6 on a successful one.

Flammable objects in the area that aren’t being worn or carried start burning.

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