Quiver of Lightning (Patreon)

Wondrous item, rare (requires attunement)

This jagged quiver zigs and zags in a lightninglike fashion. Ammunition you draw from the quiver is considered magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage. When you make an attack with the ammunition, the target takes an extra 1d4 lightning damage on a hit.

Alternatively, once on each of your turns, you can reach into the quiver and pull out a special arrow or bolt made of lightning, as part of making a ranged attack with a bow or crossbow, respectively. This special ammunition deals 2d8 lightning damage on a hit (adding your Dexterity modifier to the damage roll as normal), instead of the weapon's normal damage and without the extra 1d4 lightning damage. If the target is made of metal or wearing metal armor, the attack is made with advantage.

In addition, if you make a ranged attack with a javelin of lightning, the javelin vanishes after 1 minute (unless you retrieve it) and emerges from the quiver, falling to the floor at your feet when it does.

It's tradition to say lightning never strikes the same place twice. Unfortunately for the beleaguered encampment, that was anything but true.

Instead, it never struck from the same place twice. In the pitch-dark night a point of light would crackle to life, followed by the thrum of a longbow, a crack of thunder, and the scream of a comrade. Rarely, a far brighter light would burn through one of their commanders.

And when they sought out the bolt's origin, all they found was unmarked ground.

The lightning only stopped when there was nobody left to search.