Adagio's absolute acidic arrow .

A shimmering green arrow streaks towards 3 designated targets within range and bursts into a spray of acid causing all to make a DEX save DC 15. Make a ranged spell attack against the target. On a hit, the target takes 4d6 acid damage immediately and 4d4 acid damage at the end of its next turn. On a miss, the arrow splashes the target with acid for half as much of the initial damage and no damage at the end of its next turn. On a success, all targets must then roll a CON save DC 12 if they fail then at the end of their next turn they must take another 4d4 acid damage this will repeat until they succeed a CON save or they die.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage (both initial and later) increases by 1d4 for each slot level above 6th.