Devouring Darkness
Each creature inside a sphere when this spell is cast must make a Dexterity saving throw. On a failed save, the creature takes 6d10 piercing damage and 5d6 psychic damage and is restrained until it breaks free as unseen entities bite and tear at it from the Void. Once a successful save, the creature takes half as much damage and isn't restrained. A restrained creature can use its action to make a Strength check against your spell save DC. If it succeeds, it is no longer restrained.
When a creature enters a sphere for the first time on a turn or starts its turn in a sphere, that creature must make an Intelligence saving throw. The creature takes 5d6 psychic damage on a failed save, or half as much damage on a successful one.
Once created, the spheres can't be moved. A creature in overlapping spheres doesn't suffer additional effects for being in more than one sphere at a time.