From your outstretched hand bursts a razor-sharp icicle shedding a freezing mist, piercing creatures before you. When you cast this spell, every creature in a straight line extending 30 feet away from you takes 4d6 piercing damage and 2d6 cold damage. On a successful Dexterity saving throw, the damage is halved. In addition, creatures who failed their saving throw are impaled on the icy spear. Any impaled creatures must repeat the Dexterity saving throw each round at the start of its turn. If it fails, it is restrained for that round and takes an additional 2d6 cold damage. If it succeeds, it is free. The icicle hanging in the air makes the line’s area difficult terrain until all creatures impaled by it are free.