Assembly Ooze

Assembly Ooze CR 1

XP 400
N Medium ooze
Init +1; Senses blindsight (vibration) 60 ft.; Perception +1


AC 11, touch 11, flat-footed 10 (+1 Dex)
hp 16 (2d8+8)
Fort +8, Ref +2, Will +1
Immune ooze immunities
Weaknesses vulnerable to electricity


Speed 30 ft.
Melee pseudopod +6 (1d4+2 bludgeoning)
Space 5 ft.; Reach 5 ft.
Special Attacks disassemble


Str 14, Dex 13, Con 18, Int —, Wis 11, Cha 10
Base Atk +2; CMB +4; CMD 15 (can’t be tripped)
Skills Stealth +5
SQ assemble, compression


Assemble (Ex)

Once per day, in a process that takes 1 uninterrupted minute, an assembly ooze can craft a weapon or suit or armor sized for a Medium-sized humanoid.

There is a 25% chance that an item an assembly ooze crafts has the broken condition. Roll 1d8 on the table below to determine what kind of item the assembly ooze creates.

d8 Item Created
1–2 Light (50%) or one-handed (50%) melee weapon
3–4 Light (50%) or medium (50%) armor
5 Light (50%) or heavy (50%) steel shield
6 Masterwork light (50%) or medium (50%) armor
7 Masterwork light (50%) or heavy (50%) steel shield
8 Masterwork light (50%) or one-handed (50%) melee weapon

Disassemble (Ex)

As a full-round action, an assembly ooze can engulf an unattended non-magical metal object weighing up to 50 pounds within reach of its pseudopod. Unless the object succeeds at a DC 12 Fortitude saving throw, the ooze moves into that object’s space and completely absorbs the object. If the object weighed more than 20 pounds, this act grants the assembly ooze one more use of its assemble ability beyond its usual limit of once per day. An assembly ooze can gain a maximum of six additional uses of its assembly ability each day using this ability. In addition, if an assembly ooze succeeds at a grapple combat maneuver against a metal or technological construct, that creature takes 1d6+1 acid damage. The assembly ooze gains another use of its assemble ability for every 5 points of damage it deals in this way.


Environment any urban
Organization solitary, pair, or manufactory (3–5)
Treasure incidental

This silvery cube is a gelatinous mass of supple sections, with crackling flashes lighting it from within and playing across its surface.

Thought to have been created as a biotechnological replacement for automation processes, assembly oozes are essentially cores of nanobots suspended within blobs of animated protoplasm. As the ooze absorbs raw materials, the nanobots work at the molecular level to turn that matter into a functioning technological device, the blueprints of which have been entered into the machines’ original programming.

An assembly ooze resembles a human-sized, silvery cube, though its amorphous form allows it to slip through incredibly small openings. As it moves, surging forward on its pseudopods, random scraps the ooze has already collected sometimes float near the creature’s surface before quickly disappearing into its form. Entirely focused on absorbing and reshaping any available technology, assembly oozes usually ignore organic matter, living or otherwise, unless threatened. However, should a creature have mechanical or cybernetic elements attached to or incorporated into its physical form, an assembly ooze could very well cause that creature incidental harm in its attempts to harvest the technological parts. Sentient robots are extremely wary of assembly oozes, as their entire bodies could be targeted for processing into raw resources.

Due to sloppy programming procedures, the code embedded within an assembly ooze has an unfortunate tendency to easily become corrupted, causing the ooze to haphazardly deconstruct any nearby tech and use the pieces to build random items. The first time this occurred, several assembly oozes escaped the ensuing purge and built copies of themselves, eventually spreading to various shadowy corners of the galaxy. While these rogue oozes are not all that dangerous and have no innate malice, they are the bane of space stations, starships, weapon depots, and anywhere else technology is present. When discovered in such a location, assembly oozes are ruthlessly exterminated, lest their nonstop disassembling of all things mechanical and electronic destroy critical systems—to say nothing of the new, potentially lethal devices left in their wake. While assembly oozes are still used in some factories and its more toxic moons, their use is highly regulated.

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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