Armor Rend

You touch someone wearing metal armor (plate, splint, half-plate, and breastplate). The armor spikes inwards, causing the wearer to make a Con save of 14 + prof bonus. On a successful save, the spell fails. On a failed save, the target takes 4d8 piercing damage. On a nat 1 or 2, the armor is also damaged, reducing the target's AC by 2.