Black Ice

You create a massive storm of necrotic ice, sweeping the area. You can disperse it to up to 1000 feet.

The user attempts to freezes the solid and the creature must make a Dexterity saving throw. On a failed save, the creature takes 10d6+100 cold damage, or half as much damage on a successful save. If they roll a 5 of below, they die instantly.

Regardless of the roll, everyone but the caster(except those immune to cold damage) take 5 cold damage per round.