You encase a melee weapon you are touching in a thick layer of ice summoned from the depths of Levistus. For the spell’s duration, melee attacks with the affected weapon deal an additional 1d6 cold damage, and the weapon’s reach is increased by 5ft. 

When you stop concentrating on this spell, the conjured ice shatters. If you choose to end your concentration when you make a successful melee attack with the weapon affected by this spell, the target of the attack takes an additional 1d6 cold damage and must make a Constitution saving throw or for 1 minute, its speed is reduced by 10 feet; it can take either an action or a bonus action on each of its turns, not both; and it can't take reactions. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.