Chilling Smite

The first time you hit with a melee weapon attack during this spell’s duration, your weapon chills instantly to subzero temperatures, and the attack deals an extra 2d6 cold damage to the target. Additionally, if the target is a creature, it must succeed on a Constitution saving throw or its speed is reduced by 10' until the start of your next turn.

The spell's cold damage increases by 1d6 when you reach 5th level (3d6), 11th level (4d6), and 17th level (5d6).