Acid Bolt

You hurl a mote of acid at a creature or object within range. Make a ranged spell attack against the target. On a hit, the target takes 1d8 acid damage, and 1d4 on the subsequent round; a successful CON save negates the 2nd round of damage. A soft organic object hit by this spell begins to burn if it isn't being worn, or carried.

This spell's damage increases by 1d8 when you reach 5th level (2d8, 2d4), 11th level (3d8, 3d4), and 17th level (4d8, 4d4). Second round damage only increases by 1d4 each stage, as indicated by the second listing.