Crystal 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 magically sheds bright light in a 30-foot radius and dim light for an additional 30 feet. This light goes out when the golem is destroyed.

Any creature that starts its turn within 10 feet of the illuminated golem and can see the golem must succeed on a DC 17 Wisdom saving throw or be Blinded until the start of the creature's next turn.
A creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it can't see the golem until the start of its next turn, when it can avert its eyes again. If the creature looks at the golem in the meantime, it must immediately make the save.

The golem makes two slam attacks.

Melee Weapon Attack +10 to hit, reach 5 ft., one target. 19 (3d8 + 6) Bludgeoning damage.

The golem targets one or more creatures it can see within 10 feet of it. Each target must make a DC 17 Wisdom saving throw against this magic. On a failed save, a target can't use reactions, its speed is halved, and it can't make more than one attack on its turn. In addition, the target can take either an action or a bonus action on its turn, not both. These effects last for 1 minute. A target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.