Atroxx's Frozen Serpent

You choose a target within range. Water condenses into the frozen visage of a serpent and coils around the target, biting into it. The target must make a Dexterity saving throw. On a failed save, the target takes 2d6 cold damage and is restrained for the spell’s duration.

To break free, the target can use it's action to make a Strength check against your Spell DC.  On a success, the target breaks the serpent and is no longer restrained. Upon breaking the serpent, any creature within 5 feet takes 1d10 cold damage.