Earthen Spike

Upon casting this spell, three giant spears of earth spear up out of the ground. Each stalagmite-like spike affects a 5-foot square and tapers to a height of 15 feet. A creature that occupies a square from which a spear extends (or that is within 15 feet of the ground below) takes 2d6 bludgeoning damage per spike that impales them. a creature that takes up more than one square may be hit by one spike per square they take up. the spikes have an AC of 10 and HP of 20 + 10 for any harder material than dirt. a creature impaled by the spear needs to make a Strenght save or becomes restrained until they make the save as an action or destroy the spike impaling them.
when cast using higher-level spell slots you may make another earthen spike for each level above 3rd.