Golem, Neutronium

Family: Golems

Large construct, neutral

Armor Class 18 (combat hardened skymetal body)
Hit Points 127 (15d10 + 45)
Speed 40 ft.

20 (+5) 17 (+3) 16 (+3) 10 (+0) 10 (+0) 10 (+0)

Saving Throws Dex +6
Skills Stealth +6
Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities lightning, poison, psychic, radiant
Condition Immunities charmed, exhaustion, frightened, paralyzed, petrified, poisoned
Senses Darkvision 60 ft., passive Perception 10
Languages Understands Common but does not speak
Challenge 6 (2,300 XP)


  • Berserk. Whenever the golem starts its turn with 60 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. 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. If the golem’s creator is within 60 feet of the berserk golem (or talks to it via the Comm trait), the creator can try to calm it by speaking firmly and persuasively. The golem must be able to hear its creator, who must take an action to make a DC 15 Charisma (Persuasion) check. If the check succeeds, the golem ceases being berserk. If it takes damage while still at 60 hit points or fewer, the golem might go berserk again.
  • Combat Hardened. The golem is built for war and has a damage threshold of 5. That is, it reduces all damage by 5 per attack.
  • Comm. The golem can receive wireless communications (and thus commands from its creator) at planetary range.
  • Electrical Weakness. The golem has disadvantage on saving throws against lightning damage. If it rolls a natural 1 on the save it is stunned until the end of its next turn. This trait is only active if the golem loses its lightning immunity for any reason (see magic immunity below).
  • Light Immunity. The golem does not interact with visible light, so it is immune to radiant damage, or any other attack based on visible light (for example, prismatic spray). In any area of dim, normal, or bright light, a neutronium golem is invisible.
  • Magic Immunity. The golem is immune to any spell or spell-like effect that allows a saving throw, unless the spell specifically lists constructs as part of its description. In addition, certain spells and effects function differently against the golem, as follows:
    • If the golem is inside the area of a gravity spell (such as reverse gravity) used to increase gravity and fails its saving throw, instead of the usual effects of the spell, the golem becomes Tiny and sinks partially into the ground, becoming immobilized for the duration of the spell.
    • If the golem is inside the area of a naturally occurring gravity effect, for example a zero-g environment, and fails its saving throw (if any), in addition to the normal effects of the environment effect, it partially loses its humanoid shape as it becomes Huge (increasing its size and reach to 15 ft.) for the duration of the effect. In this state, it gains the poison condition for the duration (bypassing its normal immunity).
    • The golem automatically fails its saving throw against attacks that specifically target a robot like the discharge spell (see Appendix 1, page 154) but has a unique reaction to these spells. Discharge heals the golem for 4 (1d8) hit points per level of the spell used.
    • The golem can be targeted with a recharge spell, but this spell has a unique effect upon it. If the golem fails its saving throw, it loses its immunity to lightning and light and gains the electrical weakness trait, becoming visible as a creature of highly reflective metal until the end of its next turn.


  • Multiattack. The golem makes two attacks.
  • Iron Slam. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 22 (5d6 + 5) bludgeoning damage plus 3 (1d6) radiant damage. On a critical hit the target is knocked down and stunned until the end of their next turn.


  • Deflection. If the golem is hit by a ranged attack (including magical attacks) that would deal damage, it may make a Dexterity saving throw against a DC 10 or 8 + half the total damage that would get through (whichever is higher) to reduce the damage to zero.


Neutronium, the material found in the heart of a neutron star, is one of the densest substances in existence. Just a spoonful of it would weigh billions of tons and, if dropped onto the surface of a planet, would simply puncture the planet’s crust until it reached the core.

Further, neutronium possesses some unusual properties; because it has no electrons, it does not interact with light.

Scientists have studied neutronium for centuries, with many of them pursuing the practical goal of weaponizing the substance.

Living Darkness. A neutronium golem is invisible in light but pitch black in darkness; this quality makes it both a deadly assassin and a useful guardian. Species with natural darkvision— like drow—can easily see and interact with these golems in the darkness that is their natural environment. But when intruders trespass into the lightless chambers where a golem is stationed, any illumination they bring with them only serves to make the neutronium golem more dangerous.

Ultradense. In addition, the incredible density and neutral charge of neutronium grants the construct a number of immunities even beyond those normally associated with a golem. However, a neutronium golem does have weaknesses. By delivering a charge to the neutronium that makes up the golem’s body, its immunity to light is temporarily negated, causing it to become visible. The magical forces which give the neutronium a humanoid form are also precariously balanced, so rapid fluctuations in gravity can disrupt the golem’s body.

Finally, like many golems, it has a tendency to fly into an uncontrollable rage when damaged.

Although the process for creating neutronium golems is a relatively recent development, rumors persist that older neutronium golems exist elsewhere in the galaxy.

Based on the writings studied by the drow scientists, neutronium golems were originally created to guard sacred sites.

Section 15: Copyright Notice

Mechanical Monsters (5E) © 2023, Legendary Games; Authors: Jason Nelson, Miguel Colon, Robert J. Grady, Nicholas Hite, Matt Kimmel, Michael Mifsud, James-Levi Cooke, Dan Dillon, Mike Myler, Ismael Alvarez, Jeff Lee, John Lynch.

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