Embrittlement

You send cold energy towards a creature in the form of a biting wind. It penetrates their body, leaving nothing but the feeling of freezing temperatures in it's wake, making it agonizing to move. 

Select a creature within range that you can see. That creature must make a Constitution saving throw, taking 4d8 cold damage on a failed save, or half as much damage on a successful one. Any creature that fails the save by more than 5 is embrittled and takes 1d4 cold damage per 5ft of movement until the spell ends.

At Higher Levels. When you cast this spell with a slot of 5th level or higher, the initial damage increases by 1d8 for each slot above 4th.