Blood Golem

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

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.

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

Magic Weapons. The golem's weapon attacks are magical.

Detect Blood. The Blood Golem knows the exact location of any living thing with blood in it within 120 feet.

Blood Puddle Form. The Blood Golem can flatten out into a puddle and squeeze underneath doors and such as long as there is at least a quarter inch of a gap. While in this puddle like state the Blood Golem can not make attacks. The Blood Golem can use its move action OR standard action to turn into a puddle of blood or back into a golem form.

Multiattack. The golem makes two slam attacks.

Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.

Absorb. The golem moves into any occupied square absorbing anything of size large or smaller. It can abosrb one large creature, 2 medium, or 4 small. Any creature that ends its turn inside the blood golem takes 14(4d6) life drain damage. Any creature that does not have blood is immune to this attack. Escaping the golem requires a DC 12 Strength Save to escape (a standard action) The Blood Golem heals itself from it's absorb attack, healing itself equal to half the damage it deals from each attack.