Dark Lightning

Authority is the manifestation of power over another, and power is the expression of one’s will upon the world.
You thrust out your hands, unleashing a deadly coil of lightning infused with wrathful hate towards a creature you can see within range. The target must make a Constitution saving throw. If they fail, they take 2d8 lightning damage. If the target is below their maximum hit points, the lightning forks to another creature of your choosing within 10 feet of the target. This new target must make their own Constitution saving throw, taking 2d8 lightning damage if they fail. This process can repeat up to three times, and the same target cannot be affected twice. If a target succeeds on their saving throw and is below their maximum hit points, they take 1d8 necrotic damage instead.

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, either the lightning or necrotic damage (your choice) increases by 1d8 per slot level above 2nd.