Corrosive Blade

You brandish the weapon used in the spell’s casting and make a melee or ranged attack with it against one creature within the weapons range of you. On a hit, the target suffers the weapon attack’s normal effects, and you can cause corrosive acid to seep from the blade. The target takes an extra 1d6 acid damage, and any nonmagical armor made of metal that the target is wearing corrodes. After taking the damage, the armor takes a permanent and cumulative -1 penalty to AC, or -2 on a critical hit. If this cumulative penalty reaches -5, the armor is destroyed.

This spell’s damage increases when you reach certain levels. At 5th level, the melee attack deals an extra 1d6 acid damage to the target on a hit, and increases by 1d6 at 11th level (3d6) and 17th level (4d6).