Dark Void

You create a sphere of darkness that emits Necrotic energy. The sphere has a radius of 20 feet and is centered at a point within range.When a creature enters a space within 10 feet of the void for the first time on its turn or starts its turn there, it must succeed on a strength saving throw or be moved 5 feet towards it.When a creature enters the void for the first time on its turn or starts its turn there, it must make a constitution saving throw, taking 3d6 necrotic damage and 3d6 force damage on a failed save or half as much damage on a success.A creature cannot see through the sphere using dark vision or any other senses. While inside the sphere, a creature has the Blinded condition.

 Using a higher level spell slot: When you cast this spell using a spell slot of level 5 or higher, the necrotic damage increases by 3d6 for each slot level above 4. When you cast this spell using a 7th level spell slot, the spell does not require you to maintain concentration, and the duration is 5 minutes.