Dragon fireball

A blast of magic shaped like a dragon flashes from your hand finger to a point you choose within range and then explodes with a load boom into an explosion of dragon-fire. Each creature in a 5-foot-radius sphere centered on that point must make a constitution saving throw. A target takes 1d4 fire, 1d4 lightning, and 1d4 acid damage on a failed save.

With a 3rd level spell slot or more: Each of the damages do 1d4 more damage.