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

Multiattack. The golem makes two Slam attacks.

Slam. Melee Weapon Attack: +7  to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.

Excrete Acid(Recharge 6). The golem Excretes Acid from inside it's corals in a 10-foot cube around it. Each creature in that area must make a DC 15 Constitution saving throw, taking 27 (6d8) acid damage on a failed save, or half as much damage on a successful one. If a failed by 5 or more AC of armor and to hit of metal weapons are permanently reduced by one