Brain in a Jar

Brain in a Jar CR 5

XP 1,600
CE Tiny undead
Init +2; Senses blindsense 60 ft., darkvision 60 ft., Perception +14


AC 18, touch 14, flat-footed 16 (+2 Dex, +2 size, +4 armor)
hp 51 (6d8+24)
Fort +6, Ref +4, Will +8
Immune undead traits
Defensive Abilities channel resistance +4, madness


Speed 0 ft., fly 30 ft. (good)
Melee slam +1 (1d3-5)
Space 2 ½ ft.; Reach 0 ft.

Psychic Magic (CL 6th, concentration +10 [+14 casting defensively]) 20 PE—command undead (2 PE, DC 16), ego whip I (3 PE, DC 17), id insinuation II (3 PE, DC 17), inflict pain (2 PE, DC 16), mental block (3 PE, DC 16), mind thrust II (2 PE, DC 16), suggestion (3 PE, DC 17) Spell-like Abilities (CL 6th, concentration +10 [+14 casting defensively])

  • Constant—mage armor
  • At will—mage hand, open/close, telekinetic projectile (+8 to hit)
  • 1/day—dominate person (DC 19)


Str 1, Dex 15, Con -, Int 18, Wis 16, Cha 19
Base Atk +4; CMB +4; CMD 9
Feats Alertness, Combat Casting, Command UndeadB, Flyby Attack
Skills Bluff +10, Diplomacy +10, Fly +19, Knowledge (arcana) +13, Knowledge (history) +10, Knowledge (religion) +13, Perception +14, Sense Motive +14
Languages Aklo, Common, Necril, Undercommon, telepathy 100 ft.


Command Undead (Su)

The brain in a jar gains Command Undead as a bonus feat and can use this feat up to 7/day even though it lacks the ability to channel negative energy.

It can command a total of up to 12 Hit Dice of undead at a time, though no more than 6 Hit Dice with each use of the ability. Undead it controls are connected to it by a telepathic bond, even if they are mindless. Undead can resist its control with a successful DC 17 Will save; the save DC is Charisma-based.

Flight (Su)

The flight of a brain in a jar is magical in nature.

Madness (Su)

Anyone targeting a brain in a jar with a thought detection, mind control, or telepathic effect makes direct contact with its tortured mind and takes 1d4 points of Wisdom damage (no save).


Environment any land or underground
Organization solitary or cabal (1 plus 1-6 controlled undead and humanoids)
Treasure standard

This vessel of crystal and glass holds a murky solution of vile chemicals in its central tank. Floating within is a swollen, pulsating humanoid brain.

These vile creatures are hideous mental monstrosities preserved beyond death in exotic alchemical solutions in containers of glass and crystal, with eldritch energies giving animation and awareness to deceased cerebral tissue. Their mental powers are considerable, though their physical remains are scarcely able to move encased as they are within their jars. Their minds retain considerable psychic potency, building on any they possessed in life but also unlocking psychic potential that may have gone untapped in their mortal years. The process is highly traumatic in any event, the stress leaving the creature’s mental matrix fractured, hateful, and unstable. They work through minions whenever possible but lash out with telepathic and telekinetic fury when their plans are thwarted.

The brain itself weighs only 3 pounds, but its fluid filled jar weighs up to 20 pounds. A brain in a jar can be created by the create greater undead spell at caster level 15th—the caster must be capable of casting psychic spells or have the Psychic Sensitivity feat.

Section 15: Copyright Notice

Mechanical Monsters © 2023, Legendary Games; Authors: Jason Nelson, Tom Phillips, Mike D. Welham, Matt Goodall, Alex Riggs, Matt Daley.

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