Arcwielder

This magic weapon has a +1 to attack and damage rolls. Whenever you fire a crossbow bolt, it is converted into a mini lightning bolt as soon as it's fired. Making this crossbow only do lightning damage, and it does an extra 1d4 lightning damage. Whenever you hit with an attack against any creature, the lightning passes through them in a 40 ft. line. Any creature inside that line must make a dexterity saving throw. On a failed save they take half as much damage as the previous target to get hit with this projectile.

This crossbow has 4 charges. As a bonus action you can overcharge the weapon using one or more charges until the end of your next turn. When overcharged the 40 ft. line that is made by the lightning is extended to 100 ft. and the exter 1d4 damage dice is made into 1d6(1 charge), 1d8(2 charges), 1d10(3 charges), or 1d12(4 charges). If you hit with a direct attack (failing the dexterity saving throw not included) on a creature that is wearing half plate, full plate, scale mail, breastplate, ring mail, chain mail, or on a creature that is made of a conductive material, (Others scenarios may apply at the DM's discretion) that creature must succeed a constitution saving throw or be stunned until your next turn. Overcharging deals 2 points of lightning damage to you per charge used. You regain 1d4 expended charges daily at dawn.

Some effects of this cross require a saving throw. The DC is equal to 8 + your proficiency bonus + your dexterity modifier. If you are overcharged, you add the amount of charges you used to the DC. 

Proficiency with a Hand Crossbow allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, Damage: Lightning, Damage: Lightning, Replace Damage Type: Lightning, Damage: Lightning, Damage: Lightning, Damage: Lightning, Stunned, Ammunition, Light, Loading, Range, Vex