brain crabs of neh thalggu

This is the final fight of “Masters of Eternal Night“.  The PCs have gathered the parts of the brainlobe (The McGuffin) and triggered the last cinematic (the discovery of an ancient mind flayer nautiloid spelljammer – I took some poetic license with the ships design) but the ship’s guardians trigger to prevent non-mind flayers from using the vessel – brain golem neh thalggu crab brutes. 

3 of these brutes gave my level 17 party a run for their money. They found the leaping annoying combined with the stun.  They eventually mazed 1, held 1 then beat it to death and then just focused fire the last one.


This crab-like nightmare has a lamprey mouth, twitching eyes on its legs, and several blisters along it’s back that hold human brains. It seems to be made from brain matter..

A creation of the ancient race of mind flayers, brain golems are the most horrible of all golems. They exist purely for the desires of illithids and are unswayed from their goals, once set.

These particular brain golem’s are sculpted to look like Neh-Thelgaa and appears as a writhing forest of tendrils extending from one end of this chitin-covered creature’s body, while from the other lashes a pincer-tipped tail. Six transparent blisters adorn its back, each containing a brain floating in thick green fluid. In fact, the whole body is made up of brain tissue but is covered with a thin film of slimy skin. Although brain golems are more intelligent than other golems, they are completely unable to communicate.

Brain golems are used as muscle or guards for illithids and attack an opponent only if so ordered or if the opponent tries to get at what the brain golem is guarding. Regardless of the situation, brain golems never attack mind flayers, which limits their effectiveness in battles between members of that race.

Large construct, unaligned
Armor Class 18 (inertial armor)
Hit Points 210 (20d10 + 100)
Speed 30 ft., climb 30 ft.

24 (+7) 9 (-1) 20 (+5) 6 (-3) 11 (+0) 1 (-5)

Damage Immunities fire, poison, psychic; bludgeoning, piercing, and slashing from nonmagical attacks that aren’t adamantine
Damage Resistancesee the Resilience trait
Condition Immunities CharmedExhaustionFrightenedParalyzedPetrifiedPoisoned
Senses darkvision 120 ft., passive Perception 10
Languages understands telepathic commands but can’t speak
Challenge 16 (15,000 XP)

Immutable Form. The brain golem is immune to any spell or effect that would alter its form.
Magic Weapons. The brain golem’s weapon attacks are magical.
Psionic Absorption. Whenever the brain golem is subjected to psychic damage, it takes no damage and instead regains a number of hit points equal to the psychic damage dealt.
Resilience. The brain golem takes half damage from weapons.
Rummaging Heal. If the brain golem has no targets within 30 feet of it, it burrows and moves towards the nearest target. While burrowing it heals 20 hit points or, back to half it’s hit points if it is below half (back to its bloodied state).
Sense Weakness. In combat, brain golems are more aware of their environment than other golems. They always aim for wizards and sorcerers first, knowing that a quick strike could easily kill that physically weak class. They seem to have an innate ability to roughly determine an opponent’s condition (i.e., hit points), and they nearly always aim for the next weakest character after a wizard or sorcerer.
Spell Defence. The brain golem takes half damage from spells and makes any saving throw rolls to resist a spell with advantage. A creature attacking the golem with a spell makes the attack roll with disadvantage. Note that psionic powers bypass this defence.
Stable.The brain golem has advantage on saving throws and ability checks to resist being knocked prone.
Spider Climb. The brain golem can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Standing Leap. The brain golem’s long jump is up to 40 feet and its high jump is up to 30 feet, with or without a running start.
Tough shell. The brain golem’s shell has a damage threshold of 10. Attacks that specifically target the underbelly area near its mouth (AC 21) ignore this trait.

Multiattack. The brain golem uses mental blast if available and then makes two melee attacks.

Bite. Melee Weapon Attack: +13 to hit, reach 5 ft., one target.
Hit: 20 (3d8 + 7) piercing damage and 10 (2d10) psychic damage.

Left Claw. Melee weapon attack: +13 to hit, reach 5 ft., one target.
Hit:12 (1d10 + 7) bludgeoning damage, and the target is grappled (escape DC 19). A grappled creature automatically takes 22 (3d10 + 7)bludgeoning damage at the start of its turn.

Right Claw.Melee weapon attack: +10 to hit, reach 10 ft., one target.
Hit: 33 (4d12 + 7)bludgeoning damage. The right claw scores a critical hit on a 19 or 20.

Mental Blast (Recharge 5-6). The brain golem manifests psychic energy in a 60-foot cone. Each creature in that area takes 45 (10d8) psychic damage and must succeed on a DC 19 Intelligence saving throw or be stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. Mind flayers are immune to this attack.

Unnatural Leap. If the brain golem is more than 15 feet away from its target (for example, hanging from a wall or ceiling) as part of its movement, it can then use this action to land on its feet in a space that contains one or more other creatures. Each of those creatures must succeed on a DC 21 Strength or Dexterity saving throw (target’s choice) or be knocked prone and take 17 (3d6 + 7) bludgeoning damage plus 17 (3d6 + 7) slashing damage. On a successful save, the creature takes only half the damage, isn’t knocked prone, and is pushed 5 feet out of the brain golem’s space into an unoccupied space of the creature’s choice. If no unoccupied space is within range, the creature instead falls prone in the brain golem’s space.

Grotesque Leap. As a reaction, after a successful to hit roll is made the brain golem can leap up to its speed away from the attacker even clinging to walls if necessary. The first time a non-aberration sees this movement it must make a DC 10 Sanity check or lose 1 point of sanity. This reaction satisfies the prerequisite for unnatural leap.

The brain golems will make maximum use of their grotesque leap/deadly leap abilities to frustrate and wear down the PCs.

Inspiration: Dark Souls great crab.
Inspiration: Pathfinder neh-thalggu.


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