Crystal Storm

You summon a swarm of small crystalline shards that start flying in circles rapidly up to a 20 feet radius of a point of your choice. The area within 5 feet of the center is not affected by the spell.
Each creature that starts or ends its turn in the area must make a Dexterity saving throw. A creature takes 3d6 points of slashing damage on a failed save or half the damage on a succesful one.

Nonmagical objects in the area made of susceptible materials (such as paper, cloth, ropes, and the like) also take the damage and might be entirely cut.

At Higher Level: When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.