Vindictive Soul

Requires the user to know the "Vengeful Spirit" cantrip.

This Vindictive Soul deals necrotic damage equal to 1d6 for every 4 health the caster is missing.

You command your inner shadow to retaliate. It materializes into a 10-foot-diameter sphere that appears in an unoccupied space of your choice within range and lasts for the duration. Any creature that ends its turn within 10 feet of the shadow must make a Dexterity saving throw. The creature takes damage on a failed save, or half as much damage on a successful one.

Additionally, you can choose to move the shadow up to 50 feet, passing through any creatures in the way. If you ram the shadow into a creature, that creature must make the saving throw against the spirit's damage.

When you move the shadow, you can direct it over-or-under barriers up to 5 feet tall and levitate it across pits of any depth. The shadow absorbs light, creating darkness in a 20-foot radius, and turning bright light into dim light for an additional 20 feet.

Only one Vindictive Soul or Vengeful Spirit may be conjured by a caster at a time. Creating a new one will make the previous disappear.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the duration increases by 1 round every 2 slot levels above the 2nd. Additionally, for every 2 slot levels above the 3rd, the spell's damage die will go up one tier (d6 -> d8 -> d10 -> d12)