Cold Snap

Choose a point you can see within range. Frigid air and ice bursts from the point in a 5-foot radius. Each creature in the radius when you cast the spell must make a Constitution saving throw. On a failed save, a creature takes 4d6 cold damage and becomes restrained for the duration, as ice clings to its body. On a successful save, a creature takes half as much damage and is not restrained. At the start of each of a restrained creature's turns, it takes 2d6 cold damage.

A restrained creature can make a Strength check against your spell save DC as an action, ending the spell on itself on a success.