Level 4 Evocation (Sorcerer, Wizard)
You point at a location within range, and a glowing, 1-foot-diameter ball of acid streaks there and explodes in a 20-foot-radius Sphere. Each creature in that area makes a Dexterity saving throw. On a failed save, a creature takes Acid damage and another Acid damage at the end of its next turn. On a successful save, a creature takes half the initial damage only.
The initial damage increases by for each spell slot level above 4.