Crystal Crush

You conjure a giant, 15-foot crystal above any creature in sight.  The center of the crystal is centered on the chosen creature, and everything else in the 15-foot cubic range is also harmed by the spell. The main target must make a Constitution saving throw. The main target takes 3d10 bludgeoning damage on a failed save, and half as much damage on a successful one. The other target(s) must make a Dexterity saving throw. The other target(s) take 3d10 bludgeoning damage on a failed save, and no damage on a successful one.