Bolt

This heavy crossbow is made of metal and fires small bolts of electricity instead of normal ammunition. You gain a +1 bonus to attack and damage rolls made with this magic weapon. When you pull the string back to load the crossbow, the string crackles with energy and loads a small bolt of lightning ammunition instead. Attacks made with this crossbow deal 1d12 lightning damage instead of 1d10 piercing. In addition, whenever you make a ranged attack with this weapon against a metal target or a creature wearing metal armor, you make the attack with advantage.

This crossbow acts as a small lightning rod. If another creature within 10 feet of you takes lightning damage while you’re holding the crossbow, you take 1d6 lightning damage for every 10 lightning damage the other creature took.