Creeping ice

Any creature that you touch must succeed on a Constitution saving throw or take 10d6 cold damage or half as much on a success. On a failure magical black ice starts to incase the creature, until its next turn the creature is restrained. On the creatures next turn it can make another Constitution saving throw as its action freeing itself of the ice. If the creature fails again it becomes completely encased in black ice freezing the creature to instant death, shattering the creature breaks all non-magical equipment it carried. The black ice created by this spell cannot be destroyed or melted until the caster loses concentration, the creature succeeds its saving throws or until the spell has finished.