Decaying Acid Splash

You hurl a bubble of acid. Choose one or two creatures you can see within range. If you choose two, they must be within 5 feet of each other. A target must succeed on a Dexterity or Constitution saving throw (target's choice) or take 1d6 acid damage and have their Armor Class decreased by 1. If the target has it's AC decreased to -2 less than its max AC and is wearing armor, the target's armor gets a permanent -1 penalty. If the creature's armor gets a -5 penalty, it is destroyed by acid and cannot be repaired normally. 

This spell’s damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).