Black Lightning

A burst of jet black lightning flies from your hands. Each creature in a 100ft line must make a dexterity saving throw, taking 10d10 lightning damage and 10d10 necrotic damage on a failed save and half as much on a successful one. In addition, each creature who failed the dexterity saving throw must make a constitution saving throw. On a fail, they take the effects of the finger of death spell with a failed saving throw. On a success, they take 1d10 lightning and 1d10 necrotic damage for each of their turns until they drop to 0hp. When they do, they are stable, but must spend 3 days recuperating before they are conscious again.