A 5-foot-diameter sphere of sharp stones is drawn out of the ground into an unoccupied space of your choice within range and lasts for the duration. Any creature that ends its turn within 5 feet of the sphere must make a Dexterity saving throw. The creature takes 2d6 slashing damage on a failed save, or half as much damage on a successful one.   As a bonus action, you can move the sphere up to 30 feet. If you ram the sphere into a creature, that creature must make the saving throw against the sphere's damage, and the sphere stops moving this turn.   When you move the sphere, you can direct it over barriers up to 5 feet tall and jump it across pits up to 10 feet wide. The spell deals double damage to structures.