Deep Dive - The Gelatinous Cube
The Gelatinous Cube, a horrifying monster probably inspired by the most boring dessert ever. It silently slides down the dungeon corridors, unseen by its prey until its too late. The Gelatinous Cube will keep a dungeon clean, clearing away any of that unwanted mold, loose copper coins, and pesky adventurers.
Like that chest in the middle of the empty room which you know is absolutely, positively a mimic, you know the sword lazily floating down the hallway is too good to be true. You're right to be suspicious, because just as you reach out for the sword, your hand goes numb as it slides into the cold, slimy goo of the Cube. As the rest of you is dragged into this horrifying ooze, your body becomes alive in pain as this giant square of jiggling acid begins to melt the skin from your bones. Then it melts your bones. Fun times.
So let’s take a look at the Gelatinous Cube through the editions and see what makes this creature funny to some and scary to others.
OD&D - Gelatinous Cube
No. Appearing: 1
Armor Class: 8
Move: 6”
Hit Dice: 4
% in Lair: Nil
No. of Attacks: 1
Damage/Attack: 2-8 Special
Treasure: *See description
First appearing in the Dungeons & Dragons White Box set in the Monsters and Treasure (1974) booklet, the Gelatinous Cube is presented as more of an idea for a monster rather than an actual monster in the game and is presented as playtest material with no stats. In fact, the closest we come to actual rules is that the Gelatinous Cube would be “difficult to harm and have a large number of Hit Dice.” Who needs more information than that. Luckily, the Gelatinous Cube sees its first ‘official’ appearance in the Greyhawk (1975) supplement and provided a full and complete stat block to use.
As the name implies, these creatures were shaped very much like cubes, but not perfect as they shake and jiggle as they move. The description lists them as being about 10’ per side so as to be able to sweep clean the floor and walls of dungeon passage and that they have purposefully evolved like this because so many dungeons have that shape to them, which is just a classic hallmark of old school Dungeons & Dragons. These cubes sucked up everything, living material, dead cells, coins, various other treasures, dust, and so on. If their jell-o-like body came into contact with something, it got pulled into it which every hardened adventurer knows that if you find a cube-shaped passageway and it is mysteriously clean and free of dirt… you have an ooze problem.
Unlike many of the other creatures who just love the taste of humanoid flesh, the Gelatinous Cube isn’t as picky and will eat any creature they come across without much thought, this is largely due to the ooze not really being an intelligent creature. Any flesh, bones, or other organic material is dissolved inside of the Gelatinous Cube and, while that sounds incredibly painful, the good news is that anyone who gets caught is immediately anesthetized, happy dreams! When a creature is first hit by the fearsome cube of ooze, they must resist against it, failing that they are paralyzed and become immobilized. The touch of a cube dissolves flesh, so becoming fully enveloped by a cube is going to be certain death unless your companions want to save you from this giant block of jiggling dessert.
Luckily, fire is the bane of these creatures’ existence and, other than weapons can actually hurt these dungeon sweepers. They are immune to lightning, cold, paralyzation, fear, and polymorph attacks and with their 4 hit dice, it’s going to take a while to bring down these blobs if you are trying to save a friend from being deep-fried in acidic ooze.
You might be asking yourself why anyone would take on a Gelatinous Cube because if you see weapons or skeletons slowly drifting towards you, you should run away. Well, the problem is that adventurers like to collect coins, magic items, and the like and they just don’t dissolve, so when a cube is jiggling around their dungeon, they are full of such glorious items until they ‘purge’ themselves of such debris. This makes Gelatinous Cubes rich in treasure and their transparent bodies can easily show off all their ill-gotten gains, causing avarice in most adventurers who decide that a little jell-o isn’t going to stop them from gathering up those shiny coins.
Basic D&D - Gelatinous Cube
Armor Class: 8
Hit Dice: 4*
Move: 60' (20')
Attacks: 1
Damage: 2-8 + special
No. Appearing: 1 (1-4)
Save As: Fighter: 2
Morale: 12
Treasure Type: (V)
Alignment: Neutral
XP Value: 125
The Gelatinous Cube made its debut in Basic Dungeons and Dragons Set (1977) with very few changes from its original incarnation, it is later reprinted in the 1981 and 1983 Dungeons & Dragons Basic Set. It is still described as a 10-foot cube, though it can come in a variety of sizes to better match it’s environment if it so chooses, meaning that you might not be as safe as you previously thought in your star-shaped passageway. Just in case the game was unclear about the Gelatinous Cube’s intentions, it states that the Cube will attack any living creature it may encounter. We are forced to assume that maybe it isn’t only flesh it desires, but that it is just jealous it doesn’t have arms and legs.
This edition also lets you know it’s really difficult to notice this transparent cube of jelly, but you still get to save against being paralyzed if you walk into one of them, so that’s nice. Of course, by this point every adventurer worth their copper pieces will know the dangers of a Gelatinous Cube and will learn that walking backward and firing your crossbow is the only way to respond to these creatures. But that strategy only works when you are facing one cube, now these Gelatinous Cubes travel in packs of up to four cubes. A really clever trap would be characters coming to a 4-way intersection and cubes begin sliding down the passageways until they coalesce into the central portion and the adventurers have no place to move except into the cubes themselves.
The Gelatinous Cube also appears in the Dungeons and Dragons Rules Cyclopedia (1991) and oddly it states that the terrain you will find it in is caverns and ruins. Ruins make sense as those are just dungeons, but caverns just feel weird. Are we expected to believe that these cubes of gelatin now just live off moss, slime, and all the other ‘tasty’ things in a cave? Despite that, we do get one very useful piece of information, in a Gelatinous Cube’s lair, there will be no young cubes with mindless hunger spurring them on. Gelatinous Cubes simply split into two cubes, no copulation, no romance, and no George Michael love ballads for these ooze monsters.
AD&D - Gelatinous Cube
Frequency: Uncommon
No. Appearing: 1
Armor Class: 8
Move: 6”
Hit Dice: 4
% in Lair: Nil
Treasure Type: See below
No. of Attacks: 1
Damage/Attack: 2-8
Special Attacks: Paralyzation, surprise on 1-3
Special Defenses: See below
Magic Resistance: See below
Intelligence: Non-
Alignment: Neutral
Size: L (10’ cube)
Psionic Ability: Nil
The gelatinous cube is introduced in the Monster Manual (1977) and they remain largely unchanged from the previous editions. Though, our dungeon vacuum is provided with a bit of additional flavor when it comes to how they operate. The first thing about them is that they are listed as a scavenger, and it no longer sounds like it is doing something wrong when sliding around underground hallways. The descriptions say that it is ‘cleaning’, which we guess is one way of describing how it devours everything in its path. If there is some sort of evil wizard down at the bottom of the dungeon and they happen to be a neat freak, you can be sure that they’ll have a few of these cubes sliding around every level.
It’s not just living organisms that the cube will pick up, it also likes to devour moss and, not that it has much of a choice, everything else loose in its path. These items, be it potions, gems, coins, or loose rocks, will stay inside the cube for weeks until it is spat out, though how it ‘spits’ out anything or knows to spit something out is interesting seeing as how it is almost completely mindless. The challenge of facing a Gelatinous Cube is the same as it always has been for the characters; use common sense when you see a shiny dagger encrusted with jewels floating waist high down the hallway. Daggers don’t float.
Dragon Magazine #124 (August 1987) takes an in-depth look at the Gelatinous Cube as part of their “Ecology of” series and this article is written by Ed Greenwood. This article has a variety of cool facts you can glean from it as well as a strange story about a sage who dislikes being called out on their bullshit. The scientific name for the Gelatinous Cube is the Athcoid, a term we have never heard before. It is confirmed that these creatures have no thoughts or actual consciousness, but react to its surroundings the same way mold would react. A Gelatinous Cube will stop when it encounters cold and will seek out warmth, moving towards vibrations in the ground but has no way of hearing anything. This seems a little strange since it hates fire, but who wouldn’t enjoy a nice warm surface in a dark damp dungeon, we understand that. We’ve always figured the Cube can adjust its shape at will, but we are informed that it only morphs its form to fit its surroundings and will immediately reshape back into a cube, even when they are floating through the water they still keep their cube shape to them. Also, cubes can be found swimming through lakes, oceans, rivers, and other places which is just… great. Not only do we have to deal with jellyfish, but we also have to deal with jellycubes!
Dragon Magazine #124, 1987 TSR Inc.
Before we talk about the rest of the information about the Gelatinous Cube, let’s take a moment to talk about the setup for this story. There is an adventurer, a spellcaster named Haptooth, who likes to share his stories about adventuring through the subterranean ways of Undermountain located beneath Waterdeep. One of the scholars, Phantas, who heard his story was probably getting tired about how great of an adventurer Haptooth is, and challenged Haptooth to do something useful with his life and instead of providing conjecture, to actually do some research and science. This apparently pissed off Haptooth so much that for a year Haptooth only studied the Gelatinous Cube and provided a lecture to a group of sages, including Phantas, about how horrifying this cube is. In his closing remarks, Haptooth then upends a vial of Gelatinous Cube digestive juices on Phantas, which is what allows a cube to eat/melt flesh and bones. Haptooth then teleports away, probably laughing his ass off as he watched Phantas’ face melt off. We aren’t sure what lesson we are supposed to take from this except… don’t tell someone to do their research?
Beyond the normal things that a Gelatinous Cube is going to do, like move forward and clean a dungeon, if two cubes meet they can form into a cube that is twice as big as before and they gain double hit points and will happily stay as a big cube for a week before it splits back into two cubes and they go their separate ways. We suppose it takes them that long to figure out you can’t eat another Gelatinous Cube, no matter how hard you try. But that’s not the only time the cubes will split, about every 6 years a cube will split into two ‘baby’ cubes that are slightly smaller, about 8-feet on each side, and they will fully grow into a 10-foot cube after 3 months. Interestingly the Gelatinous Cube is also called an immortal creature, as nothing short of starvation or death by adventurers can end its existence. So after the apocalypse, there will be only roaches, twinkies, and Gelatinous Cubes. We call dibs on the twinkies and roaches.
2e - Gelatinous Cube
Climate/Terrain: Subterranean
Frequency: Uncommon
Organization: Solitary
Activity Cycle: Any
Diet: Omnivore
Intelligence: Non- (0)
Treasure: Nil (incidental)
Alignment: Neutral
No. Appearing: 1
Armor Class: 8
Movement: 6
Hit Dice: 4
THAC0: 17
No. of Attacks: 1
Damage/Attack: 2-8
Special Attacks: Paralyzation, surprise
Special Defenses: See below
Magic Resistance: Nil
Size: L (10’ cube)
Morale: Average (10)
XP Value: 650
Monstrous Compendium Volume 1, 1989 TSR Inc.
The Gelatinous Cube first appears in 2nd edition in the Monstrous Compendium Volume 1 (1989) and then is republished in the Monstrous Manual (1993) and is no longer alone! The Gelatinous Cube is no longer the solo ooze of death on the block and now has a variety of other oozes, slimes, and jellies to share their dungeon space with. Of course, it’s a bit insulting that such an iconic jelly gets lumped in with such common goos as the green slime and gray ooze, but sometimes you gotta take one for the team. There are a few new bits of lore to explore, but otherwise, the cube is just copied over from 1st edition.
The biggest change to the Gelatinous Cube is how it reproduces, and no you don’t have to worry about seeing two cubes getting it on in the dark dungeon corridors. Instead, a cube develops buds on its surface which then are deposited in the dungeon as small, rubbery cubes. They are typically left behind in dark corners or on piles of trash and they are left to defend themselves, unless the Gelatinous Cube circles by and accidentally swallows it back up. These cubes then spend an undetermined amount of time growing into large cubes and then making their own young and abandoning them in the dungeons in a vicious cycle of parental absence.
Monstrous Manual, 1993 TSR Inc.
Oozes, jellies, and goos are all creatures of dungeons, but you might wonder how they all got there. The Monstrous Manual goes on to explain that oozes are the experiments of crazed wizards who were trying to create something to protect their dungeons and that the Gelatinous Cube is greatly loved for the fact it retains it’s cube shape and doesn’t squeeze itself under doorways and get into places it doesn’t belong. Beyond that, the cube also now leaves behind a trail of slime on the walls and floor it travels over, much like how a snail does. Unlike a snail, a Gelatinous Cube cannot climb the walls or cling to the ceiling in order to access the mold so high up, so it is forced to grow up tall, about 10-feet, so it can feast on the mold found up there. Also, any snails who think they can outrun the cube or attempt to escape its insatiable hunger.
3e/3.5e - Gelatinous Cube
Large Ooze
Hit Dice 4d10+32 (54 hp)
Initiative -5
Speed 15 ft. (3 squares)
Armor Class 4 (-1 size, -5 Dex), touch 4, flat-footed 4
Base Attack/Grapple +3/+7
Attacks: Slam +2 melee (1d6 plus 1d6 acid)
Full Attack: Slam +2 melee (1d6 plus 1d6 acid)
Space/Reach: 10 ft./5ft.
Special Attacks: Acid, engulf, paralysis
Special Qualities: Blindsight 60 ft., immunity to electricity, ooze traits, transparent
Saves: Fort +9, Ref -4, Will -4
Abilities: Str 10, Dex 1, Con 26, Int -, Wis 1, Cha 1
Skills: -
Feats: -
Climate/Terrain: Underground
Orgnization: Solitary
Challenge Rating: 3
Treasure: 1/10th coins, 50% goods (no non-metal or non-stone), 50% item (no non-metal or non-stone)
Alignment: Always neutral
Advancement: 5-12 HD (Huge); 13-24 HD (Gargantuan)
Level Adjustment: -
Monster Manual, 2003 WotC
The Gelatinous Cube keeps up the trend of showing up in the first of the Monster Manuals and it’s no different for 3rd edition where it arrives in the Monster Manual (2000/2003). The Gelatinous Cube is still considered an ooze, not even qualifying as a jelly or a slime, and while it’s understandable that WotC wants to condense certain creature types, but they call the creature “transparent protoplasm”. Protoplasm isn’t an ooze, it’s a colorless material that makes up the living parts of a cell, and includes cytoplasm, nucleus, and organelles. While, we don’t know what any of them at means, we are confident it isn’t ooze.
The Gelatinous Cube’s main attack is to engulf its prey, though it now gains the ability to create a pseudopod, which just means it can create an appendage and slap you around with it. Strangely, this appendage has no mention of being able to grab a target or being sticky, which means that all it can do is flail it around. Too bad for the cube as it has a horrible speed and a snail can easily outpace the cube, nevermind a healthy group of adventurers going for a leisurely stroll through the dungeon. Honestly, we aren’t sure how adventurers would get caught by a Gelatinous Cube unless they were taking the lead and weren’t paying attention, which is an important lesson for all adventurers to learn. Stay in the middle of the group and let someone else go first, preferably someone who has a bit of meat on them and the cube will have to take a bit of time to eat so you have plenty of time to run away.
One major change from 3e to 3.5e is that the Gelatinous Cube goes from a huge ooze to a large ooze, but its actual size of a being a 10-foot cube doesn’t change. Honestly, that was probably a misprint on WotC’s behalf, though the other major change isn’t. In 3e, a ‘huge’ Gelatonious Cube weighs 10,000 pounds. That’s a lot of ooze. In 3.5e, they now weigh 15,000 pounds which is an incredible amount of weight… but, it still isn’t that much. If the cube was made of water, it would weigh over 60,000 pounds! So… whatever that ooze is, it’s pretty light weight.
4e - Gelatinous Cube
Level 5 Elite Brute
Large natural beast (blind, ooze) / XP 400
Initiative +4 / Senses Perception +3; tremorsense 5
HP 152; Bloodied 76
AC 18; Fortitude 18, Reflex 16, Will 15
Immune gaze; Resist 10 acid
Saving Throws +2
Speed 3; also see engulf
Action Points 1
Slam (standard; at will) +10 vs. Fortitude; 1d6+2 damage, and the target is immobilized (save ends).
Engulf (standard; at will) ✦ Acid
The gelatinous cube attacks one or two Medium or smaller targets; +8 vs Reflex (automatically hits and immobilized creature). On a hit, the target is grabbed and pulled into the cube’s space; the target is dazed and takes ongoing 10 acid damage until it escapes the grab. A creature that escapes the cube shifts to a square of it choosing adjacent to the cube. The cube can move normally while creatures are engulfed within it.
Translucent A gelatinous cube is invisible until seen (Perception DC 25) or until it attacks. Creatures that fail to notice the gelatinous cube might walk into it, automatically becoming engulfed.
Alignment Unaligned / Languages -
Skills Stealth
Str 14 (+4) Dex 14 (+4) Wis 13 (+3) Con 16 (+5) Int 1 (-3) Cha 1 (-3)
Introduced in 4th edition in the Monster Manual (2008) and there is sadly scant information in the 4th edition that has not been covered in the previous editions, though it’s pseudopod has been removed. The little information provided is that they most likely attack because they are hungry and you disturbed them as they were toiling away, keeping the dungeon clean of all organic and non-organic material. Or maybe they just hate you because you have arms and legs and they don’t have a pseudopod anymore.
Monster Manual, 2008 WotC
The Gelatinous Cube then shows up again in the Monster Vault (2010) which is a supplemental book talking about the most iconic monsters of Dungeons & Dragons and providing some story information for a DM to add into their game. Beyond the usual information we are given about the cube, we also find out that oozes are one of the easiest creatures to summon and that sages will often summon them and then trick them into specific locations in dungeons. They’ll then use braziers and other sources of heat in order to ‘steer’ the Gelatinous Cube and ensure that it stays patrolling in a specific section of the dungeon.
Dungeon Magazine #188, 2011 WotC
One other tidbit of note regarding the Gelatinous Cube can be found in the Demonomicom of Iggwilv found in Dungeon Magazine #188 (March 2011). A series ran in the magazine for months, featuring a number of demons and providing detailed background on them. This article featured Juiblex, the god of oozes and slimes. Since our Gelatinous Cube is an ooze, Juiblex has control over our clear jelly dessert. Along with other oozes and slimes, you can find Gelatinous Cubes in hell, residing in the Slime Pits, along with their god. Most demons hate Juiblex, seeing him as a nuisance though they often find the best of dealing with him is to simply move out of his way and allow the ooze demon to move past them… which is a great strategy that everyone else should attempt when dealing with the cube of very slow-moving death.
5e - Gelatinous Cube
Large ooze, unaligned
Armor Class 6
Hit Points 84 (8d10+40)
Speed 15 ft.
STR 14 (+2) | DEX 3 (-4) | CON 20 (+5 ) | INT 1 (-5) | WIS 6 (-2) | CHA 1 (-5)
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, prone
Senses blindsight 60 ft. (blind beyond this radius), passive Perception 8
Languages -
Challenge 2 (450 XP)
Ooze Cube. The cube takes up its entire space. Other creatures can enter the space, but a creature that does so is subjected to the cube's Engulf and has disadvantage on the saving throw. Creatures inside the cube can be seen but have total cover. A creature within 5 feet of the cube can take an action to pull a creature or object out of the cube. Doing so requires a successful DC 12 Strength check, and the creature making the attempt takes 10 (3d6) acid damage. The cube can hold only one Large creature or up to four Medium or smaller creatures inside it at a time.
Transparent.. Even when the cube is in plain sight, it takes a successful DC 1 5 Wisdom (Perception) check to spot a cube that has neither moved nor attacked. A creature that tries to enter the cube's space while unaware ofthe cube is surprised by the cube.
Pseudopod. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 10 (3d6) acid damage.
Engulf. The cube moves up to its speed. While doing so, it can enter Large or smaller creatures' spaces. Whenever the cube enters a creature's space, the creature must make a DC 12 Dexterity saving throw. On a successful save, the creature can choose to be pushed 5 feet back or to the side of the cube. A creature that chooses not to be pushed suffers the consequences of a failed saving throw. On a failed save, the cube enters the creature's space, and the creature takes 10 (3d6) acid damage and is engulfed. The engulfed creature can't breathe, is restrained, and takes 21 (6d6) acid damage at the start of each of the cube's turns. When the cube moves, the engulfed creature moves with it. An engulfed creature can try to escape by taking an action to make a DC 12 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the cube.
Monster Manual, 2014 WotC
The Gelatinous Cube continues the proud tradition of appearing in the first Monster Manual (2014) for each edition. The cube’s lore has remained the same, and in fact, several paragraphs and sentences are directly lifted from the past Monster Manuals from 3e and 4e, which is one way of ensuring lore stays consistent across the editions we suppose.
With 5e, the rules for dealing with a Gelatinous Cube are pretty bare bones… get it? Cause it’ll bare your bones if you get caught? Alright, we’ll stop. Truth be told, fighting a Gelatinous Cube is pretty fleshed out… We’re sorry, we won’t do it again, just couldn’t pass up the opportunity to ooze another joke out. Fact is, if you’ve read all the way up to this point, you know all the lore that has ever been created for the Gelatinous Cube and probably ever will be. The cube of acid is a simple monster that is as much a staple of Dungeons & Dragons as dungeons and dragons are.
Monster Manual, 2014 WotC
Now, we said there isn’t much more to talk about the Gelatinous Cube, but we would be remiss if we didn’t point out that they get their pseudopod back… and yet they still want to kill you. Maybe it wasn’t because you had limbs and they didn’t, maybe they are just really hungry and you’d make a great snack inside of the jiggly cube-o-jell-o. It probably comes down to Gelatinous Cubes having next to no mental stats and are just a senseless creature who glides through the dungeons grabbing any and all organic matter they can find. They fight to the death because they have no understanding that even though they might be sentient acid, they are still mortal. If the cube can ooze, you can kill it.
In the limited information provided, it’s pretty much confirmed that these creatures are the spawn of the demon lord Juiblex, though the text also talks about how they could be natural creatures, and that’s not a world we want to live in. Regardless if Juiblex created all slimes, it is the only thing ‘alive’ that can control a Gelatinous Cube, even being able to provide it a modicum of guile and intelligence. When the demon lord does that, look out because they go from non-intelligent creatures surviving solely on instinct to one that looks at you and your friends with bad feelings and evil intent. Sure, it’s a giant cube of goo but when something, even the Gelatinous Cube, is controlled by a demon, bad things usually follow.
So there you have it, the Gelatinous Cube. It may not be the strongest or smartest of creatures, but as you have probably figured out, it doesn’t need to be. Once it swallows you up, it's hard to get free and dying by acid, digestive juices, or whatever you want to call it is a slow and painful way to die. For low level parties, the Gelatinous Cube can provide a moment of levity in the dungeon, for who could be scared of dessert? Of course, everyone stops laughing when the barbarian’s skull begins melting in front of them… and then it begins floating towards them.
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