Grave Golem

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.

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

Multiattack. The Golem makes two slam attacks.

Slam. Melee Weapon Attack: +10 to hit, reach 5 ft., # target. Hit: 21 (3d10 + 6) bludgeoning damage.

Vision Of The End (Recharge 5-6). The golem targets one creatures it can see within 10 feet of it. The target must make a DC 15 Wisdom saving throw against this magic. On a failed save, the target is considered frightened and cannot move closer to the golem, and has disadvantage on attack rolls against the golem. This effect lasts 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. 

Corpse Breath (Recharge 6). The golem releases a sickening miasma from it's mouth in a 20 foot cone in front of it. All affected targets must make a DC 14 Constitution saving throw against this poison. On a failed save, the target takes 2d8 necrotic damage and is considered Poisoned until the end of their next turn.