Caustic Smite

As a bonus action, you conjure magical acid to ooze on the weapon you strike with, dealing an extra 4d4 Acid damage to the target. In addition, the target must succeed on a Dexterity saving throw. On a failed save, the target takes an additional 2d4 Acid damage at the end of its next turn.

At Higher Levels. When you cast this spell using a spell slot of 3rd–Level or higher, the initial Acid damage increases by 2d4 and the extra Acid damage at the end of the target’s next turn increases by 1d4 for each slot level above 2nd–Level.