Crystal Nova

Ice Crystals form on your pointing finger to a point you choose within range and then freezing the air around creating an icy implosion of frost. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 7d6 cold damage on a failed save, or half as much damage on a successful one. creatures have their movement speed reduced by 10 until the start of your next turn.

The cold spreads around corners. It freezes any wet objects in the area that aren't being worn or carried.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.