Blood Golem

Berserk. Whenever the golem starts its turn with 40 hit points or fewer, roll a d6. On a 6, the golem goes berserk. On each of its turns while berserk, the golem attacks the nearest creature it can see and gets an extra attack. If no creature is near enough to move to and attack, the golem attacks an object, with preference for an object smaller than itself. Once the golem goes berserk, it continues to do so until it is destroyed or regains all its hit points.

Reckless. At the start of its turn, the blood golem can gain advantage on all melee weapon attack rolls during that turn, but attack rolls against it have advantage until the start of its next turn.

Regeneration. The blood golem regains 10 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight or running water. If the blood golem heales or takes damage from holy waterr, this trait doesn't function at the start of the blood golem's next turn.

Rancid Degeneration. At the end of each of the blood golem's turns, each creature within 5 feet of it takes 11 (2d10) necrotic damage, unless the blood golem has healed or taken damage from holy water since the end of its last turn.

Immutable Form. This Golem is immune to any spell or effect that would alter its form.

Liquid Form . The Blood Golem can move through a space as narrow as 1 inch wide without squeezing.

Wounding Presence. When a living creature within 30 feet of the blood golem takes Slashing or Piercing damage they take an additional 1d8 damage.

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.

Congealing Mass. The Blood Golem gains and loses size as its health fluctuates. A full health blood golem is always large. If the total of its Temporary hit points and Hit Points is less than 50 it becomes Medium and its Blood Blades deal 1d8 less slashing damage. If a combination temp HP and regular HP ever exceed its maximum hit points it becomes Huge gaining 5 feet of reach and dealings an additional 1d8 slashing damage with its Blood Blades.

Blood monster: it can heal HP over its max hp.

Multiattack. Blood Golem makes two attacks with its Blood Blades or uses its Siphon ability once. If the Blood Golem cannot reach any enemies, it may sacrifice ten hit points or temporary hit points to attack once with a Blood Blade extending its range to 30 /60 feet for the attack

Blood Blades. Melee Weapon Attack: +8; to hit, reach 5 ft., one target. Hit: 16 (2d8 + 4) slashing damage + 1d6 necrotic damage.

Siphon (Recharge 5-6) The Blood Golem drains life from those around it. It attempts to pull blood from their bodies and into itself. This deals 6d8 Necrotic Damage to all creatures within 30 feet. A DC 16 constitution saving throw halves this damage. A creature has disadvantage on this save if it is below half of its maximum hit points. The Blood Golem gains temporary hit points equal to half the amount of damage dealt this way.

Heart Beat: Melee spell Attack: +7; to hit, reach 5 ft., one target. Hit: 15 (12d4-15)  necrotic damage.

Blood Drain. If a living creature within 30 feet of the Blood Golem that the Blood Golem can see is reduced to 0 hit points or fails a death saving throw. It may take this reaction to siphon the last bit of its life. This gives the creature one failed death saving throw and heals the golem for 8d4+4. If this would kill the creature it heals an extra 36 hit points.