Thorn Barrier

You conjure up a surge of thorns that crashes down on an area within range. The area can be up to 30 feet long, up to 10 feet wide, and up to 10 feet tall. Each creature in that area must make a Dexterity saving throw. On a failed save, a creature takes 5d8 piercing damage and is knocked prone. On a successful save, a creature takes half as much damage and isn’t knocked prone.