Bone Golem

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

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

The golem's weapon attacks are magical.

The golem makes two slam attacks.

Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 18 (3d8 + 5) bludgeoning damage.

The golem targets one creature it can see within 60 feet of it. A prison of magical bones surrounds the creature. The target must make a DC 15 Dexterity saving throw or become restrained. The restrained creature can break free by succeeding on a DC 20 escape check, or by destroying the bone prison (AC 20; 50 hit points; immunity to poison and psychic damage). The golem can only have one bone prison active at a time.It may dismiss the bone prison as a bonus action.