Cold Absorption. Whenever the golem is subjected to cold damage, it takes no damage and instead regains a number of hit points equal to the cold damage dealt.

Immutable Form. The golem is immune to any spell or effect that would alter its form.

Magic Resistance. The golem has advantage on saving throws against spells and other magical effects.

Magic Weapons. The golem's weapon attacks are magical.

Cold Body. When ever a creature makes a melee attack or touches the golem, that creature must take 13 (2d6 +7) cold damage. 

Avoidance. If the Golem is subjected to an effect that allows it to make a saving throw to take only half damage, it instead takes no damage if it succeeds on the saving throw, and only half damage if it fails

Multiattack. The golem makes three melee attacks.

Slam. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage plus 13 (2d6 + 7) cold damage.

Mace. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 23 (3d10 + 7) bludgeoning damage plus 13 (2d6 + 7) cold damage.

Cold Breath (Recharge 6). The golem exhales poisonous gas in a 15-foot cone. Each creature in that area must make a DC 19 Constitution saving throw, taking 57 (12d8) cold damage on a failed save, or half as much damage on a successful one.

Parry. The golem adds 6 to its AC against one melee attack that would hit it. To do so, the golem must see the attacker and be wielding a melee weapon.