Swarmed Infestation

You conjure a cloud of random insects forming a 15 ft. diameter half-sphere. Any creature that starts its turn inside takes 3d6 piercing damage and loose 10 ft. of movement speed on a failed dex save and half as much on a successful one without the movement penalty. You can move this Sphere up to 15 ft. as a bonus action but its centre may never be more than 60 ft away.