Coal golem

Immutable Form. The golem is  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.

Ignite. If the golem takes 10: slashing, piercing, from a steel weapon, it will ignite. Any creature within 10 Ft while the golem is ignited will take 2d6 fire damage. The golem will remain ignited for 1d4 rounds after which it can not ignite until the next dawn.

Multiattack. The golem makes two attacks.

Shield Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 16 (2d10 + 5) bludgeoning damage. If the target is a creature, it must succeed on a DC 15 Constitution saving throw or have its hit point maximum reduced by 5. The target dies if this attack reduces its hit point maximum to 0. The reduction lasts until removed by the greater restoration spell or other magic.

Shield Edge. Ranged Weapon Attack: +4 to hit, one target, Hit: 2d8+3

Parry. 18 Dex DC. On a successful save the golem reduces any damage by half that turn.