A iridescent mist leaves your mouth and is channeled through touch to rust metal in a radius of 1 ft from the point of contact. This, in effect, reduces the AC of the Strength check to break the material. If used on a metal construct, making a melee attack with your spell casting modifier + your unarmed attack bonus, it deals 3d10 acid damage. Magic items are unaffected by this spell.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the radius increases by 1d4 ft and the damage increases by 2d10 for each slot level above 3th.

Fun Fact: IRL acid really does just rust (oxidize) stuff really fast.