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.
Siege Monster. The golem deals double damage to objects and structures.
Multiattack. The golem makes two melee attacks.
Slam. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage.
Crystal Shards (Recharge 6). The golem unleashes shards of amethyst crystal in a 15-foot cone. Each creature in that area must make a DC 18 Dexterity saving throw, taking 36 (8d8) slashing damage on a failed save, or half as much damage on a successful one.