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!