Expel Core

You create a bolt of lightning that arcs toward a target of your choice that you can see within range. The target must make a Dexterity saving throw. The creature takes 2d8 lightning damage on a failed save, or half as much on a successful one.

Lightning arcs from the creature, and you are able to target up to 2 additional creatures within 20 feet. Those creatures must make Dexterity saving throws. Each target takes 1d8 lightning damage on a failed save, or half as much on a successful one.

In expending such a high charge you completely drain yourself and your health instantly drains to 1 HP and you have 1 level of exhaustion.

Usable once per long rest.