The ground in a 50-foot radius centered on a point of your choice within range erupts with sharpened wood. Each creature in the area when the spines first appear must make a Dexterity saving throw. On a failed save, a creature takes 8d6 piercing damage. On a successful save, it takes half as much damage. The area becomes difficult terrain for the duration. When a creature moves into or within the area, it takes 1d6 piercing damage for every 5 feet it travels.   When a creature is knocked prone in the area it must succeed on a Dexterity saving throw or take 6d6 piercing damage. On a successful save, it takes half as much damage. When a creature attempts to stand up in the area, it must first succeed on a Strength ability check against your spell save DC. On a failed check, the creature takes 3d6 piercing damage its speed is reduced to 0 until the start of its next turn.