Chill Blade

You imbue the weapon used in the spell’s casting with elemental frost, and make a melee attack with it against one creature within 5 feet of you. The weapon is now treated as magical for determining the target's resistance. On a hit, the target suffers the weapon attack’s normal effects, and must make a Constitution saving throw or suffer disadvantage on its next melee attack.

This spell deals additional frost damage when you reach certain levels. At 5th level, the attack deals an extra 1d8 cold damage to the target on a hit, and this damage increase by 1d8 at 11th level (2d8) and 17th level (3d8).