Spectral skeletal arms emerge from the ground in a 20-foot-radius circle, centered on a point you can see within range. The arms grasp at creatures within the area, except for undead creatures, which ignore the effects of this spell. The area is difficult terrain.   When a creature enters the area for the first time on a turn or starts its turn there, it must make a Strength saving throw. On a failed save, a creature takes 3d6 necrotic damage, and is dragged by the hands to any unoccupied space within the area that you choose. On a successful save, a creature takes half as much damage and is not moved.   Until the spell ends, you can use your action to force each creature within the area to immediately make a save against this spell.