Cryoball

A bright streak flashes from your pointing finger to a point you choose within range and then blossoms with a low roar into an explosion of ice. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 6d6 cold damage on a failed save, or half as much damage on a successful one.

After a failed save, a target has its Speed is reduced by 10 feet until the start of your next turn.

The ice spreads around corners and douses exposed flames in the area.

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.