Shocking Grasp

You shroud your hands in a crackling field of lightning. Make a melee spell attack roll. On a hit, the target takes 2d12 electricity damage. If the target is wearing metal armor or is made of metal, you gain a +1 circumstance bonus to your attack roll with shocking grasp, and the target also takes 1d4 + the item's level − 1 persistent electricity damage on a hit. On a critical hit, double the initial damage, but not the persistent damage.