Acid Bubble

A bubble of acid slowly floats toward a point within range. At the start of your next turn, the bubble explodes. Each creature in a 10-foot-radius Sphere centered on the targeted point must make a Dexterity saving throw. On a failed save, a creature takes 4d4 Acid damage, or half as much on a successful one.

Using a Higher-Level Spell Slot. The damage increases by 1d4, and the radius increases by 5 feet, for each spell slot level above 1.