Dance of Arrows

You chant a minor incantation, channeling your powers into a single arrow. Upon finishing the casting, spectral duplicates of your arrow appear at a point in the sky you can see within range, forming a 20-foot radius cylinder up to 40 feet tall. Each creature in the cylinder must make a Dexterity saving throw. A creature takes 6d6 piercing damage on a failed save, or half as much damage on a successful one.