Corrosive Ray

A ray of oxidizing red-brown energy lashes out toward a creature within range. Make a ranged spell attack against the target. On a hit, the target takes 5d10 acid damage and must make a Dexterity saving throw. On a failed save, a suit of nonmagical armor, shield, or weapon of your choice that it is wearing or carrying and is at least partially made of metal begins to rust.

An affected nonmagical weapon takes a permanent and cumulative -1 penalty to damage rolls. If its penalty drops to -5, the weapon is destroyed.

An affected nonmagical armor or a shield takes a permanent and cumulative -1 penalty to the AC it offers. An armor is destroyed if the penalty reduces its AC to 10 and a shield is destroyed if the penalty reduces its AC to 0.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d10 for each slot level above 4th.