Tide of the Damned

You summon the spirits of the fallen in an area centred on you.. The area is 20 feet long, 20 feet wide, and 10 feet tall. Each creature in that area must make a Dexterity saving throw. On a failed save, a creature takes 4d8 necrotic damage. On a successful save, a creature takes half as much damage. As a bonus action, on the same turn as the spell was cast, you may charge the spirits forward a distance equal to the remained of your walking speed. Any new creatures of your choosing caught up in this advance must also make a Dexterity saving throw or take 4d8 necrotic damage.