Acid Lash

You create a ten-foot long, vividly purple, glowing line of magical force, which you can use as a whip. You use your spell attack modifier to attack.

On a hit, it does 2d10 acid damage. If it does at least 15 points of damage, and if the target is wearing armor, the armor’s AC is permanently reduced by one level of effectiveness. If it is reduced to AC 10, it is destroyed.