Ethryn's Mistral Mists

A Frigid fog bank briefly envelops a twenty-foot radius sphere centered on a point you choose within range. The fog spreads around corners. Creatures caught in the fog must make a Constitution saving throw. On a failed save a creature takes 6d6 cold damage. In addition, the creature flash-freezes. A creature who freezes as part of this spell is grappled until they use an action to break the ice encasing them. On a successful save a creature takes half damage and it does not freeze

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.