You brandish the ammunition used in the spell’s casting and make a ranged attack with it against one creature within the weapon's range. On a hit, the target suffers the weapon attack’s normal effects and also takes an additional acid damage equal to your spellcasting ability modifier.  The target also takes 1d6 acid damage at the end of it's next turn.  

This spell’s damage increases when you reach certain levels. At 5th level, the ranged attack deals an extra 1d6 acid damage to the target on a hit. Both damage rolls increase by 1d6 at 11th level (2d6 and 2d6) and again at 17th level (3d6 and 3d6).