Chillblain Breastplate

This armor is forged from overlapping blue steel plates or blue rings and has a frosted appearance. While wearing this armor, you gain a +1 bonus to AC, and you have resistance to cold damage. In addition, when a creature hits you with a melee weapon attack, it must succeed on a DC 15 Constitution saving throw or become numbed by the supernatural cold radiating from the armor. A creature numbed by the cold can use either an action or bonus action on its turn, not both, and its movement speed is reduced by 10 feet until the end of its next turn.