Viking Smite ~

AKA "Freezing Smite" or "Frost Smite". The next time you hit a creature with a melee weapon attack during the spell’s duration, your weapon frosts over with ice, and the attack deals an extra 1d6 cold damage to the target and causes the target to become frostbitten. At the start of each of its turns until the spell ends, the target must make a Constitution saving throw. On a failed save, it takes 1d6 cold damage. On a successful save, the spell ends. If the target heals, or if some other effect melts the ice on it (such as the target being burned or hit with fire damage), the spell ends.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the initial extra damage dealt by the attack increases by 1d6 for each slot.

This spell is homebrew and not finalized, discuss with your dungeon master before adding to your game 
~ B