The Gelatinous Cube in Dungeons & Dragons is a bit of a legendary monster. In fact, many DMs enjoy the satisfaction that comes from navigating their party into an encounter with this gelatinous foe. But just how much do you know about this mysterious ooze?
This monster has a reputation for being the butt of jokes. After all, it’s a squishy see-through cube of jelly (or Jell-O for our American friends). Harmless right? Wrong. Despite appearances, the gelatinous cube is extremely deadly and taking it on could spell the end for your character.
As for bards, well… seduction attempts are likely to be fatal.
Here’s a joke which may or may not get you in trouble with your DM (sorry, not sorry):
Why couldn’t the Bard seduce the Gelatinous Cube? Because cubes are platonic solids… *badum, tish*
Table of Contents
Gelatinous Cubes: Keeping dungeons tidy since 1974
Gary Gygax introduced the Gelatinous Cube in the earliest DnD sets in 1974. Unlike other monsters, which are based on fictional creatures from myths and legends, this one is a Gygax special, invented from scratch to poke fun at map grids.
Gelatinous cubes are 10ft x 10ft… cubes, which is the standard size of any dungeon corridor, which means it specifically takes advantage of its environment. They don’t hunt their prey in the same way as other monsters, nor do they hunt in packs like owlbears. Rather, they make circuits of the dungeons they live in, like a robotic vacuum cleaner sucking up anything in their path; except this one absorbs all organic material it encounters, not just dust and lint.
If a dungeon seems devoid of loot or a little too empty, you may be about to encounter a gelatinous cube… the cube traverses an area and digests any organic matter in its way, if you do get sucked in, it’s a slow suffocating death too. However, your gear, weapons, or special items will be eternally preserved, waiting for the next adventurer to find.
How to defeat a gelatinous cube
One word: FIRE!
If you’re looking to take on a gelatinous cube in order to loot all its goodies, be sure you have a fire mage in your party or equip yourself with the following:
- Flaming arrows
- Fire spells (Fireball, Fire Bolt, Fire Storm etc.)
- Staff of Fire
- Wand of Fireballs
- Alchemists Fire (Flask)
- Flame Tongue
What is the best way to kill a gelatinous cube?
Fire is absolutely your best friend. Fire arrows, fire spells, burning oil – kill it with fire!
Can you trap a gelatinous cube with stairs?
Much like its robotic vacuum cleaner counterpart, it can’t traverse staircases…or can it?
In Dungeon Denizens Revisited, published by Paizo Publishing, there is a whole section dedicated to this all-consuming notorious ooze cube. And it turns out that in some cases they can move up and down stairs.
“[Gelatinous cubes] can, however, move up and down stairs with no trouble, provided such impediments are less than half the height of the cube. While they can compress themselves to fit into narrow or low-ceilinged corridors, gelatinous cubes cannot fit into spaces smaller than half their width.” (Dungeon Denizens Revisited, Pg. 16-21)
Which means it can’t pass through staircases or obstructions with a width or height larger than 5ft.
Will a barricade stop a gelatinous cube?
Clever adventurers work out pretty quickly that it only absorbs organic matter and that it cannot pass through stone or metal. As such it is technically possible to trap a cube and box it in with a Wall of Stone or Stone Shape spell.
Can you cast spells in a gelatinous cube?
If you’re unlucky enough to find yourself absorbed into a gelatinous cube, you’ll want to get out as quickly as possible as you will take 10 (3d6) acid damage and become engulfed. This is particularly worrying given an engulfed creature can’t breathe and is also Restrained, as well as taking a whopping 21 (6d6) acid damage at the start of each of the cube’s turns.
Because engulfed players cannot breathe, it follows that they cannot cast spells. A player within 5 feet of the cube can use up an Action to pull another player or object out of the cube but doing so requires a successful DC 12 Strength check as well as taking 10 (3d6) acid damage. There’s nothing stopping characters outside of the cube from casting spells however, so you’ll want to ensure your mages don’t get too near, lest they be absorbed into the transparent goop forever!
How to use a gelatinous cube to your advantage
Obtain weapons and gear
Unlike another large ooze monster, the black pudding (which only engulfs items that aren’t magical), the gelatinous cube only digests the organic matter it engulfs. As such, it often has lots of cool weaponry, armour, items and equipment inside. Being transparent, explorers can often see what’s up for grabs if they decide to take on this foe. But beware of temptation…as taking it on is a risk; a gelatinous cube can absorb up to 4 party members at any one time depending on their size!
Lead enemies into their path
Given the fact it sucks up anything in its way, one of the best ways to use a gelatinous cube to your advantage is to lead enemies towards it. Though this of course will depend on the environment of the dungeon and how your DM has laid it all out. And let’s face it, your party’s dexterity! In the 4e supplement Monster Vault, oozes are described as one of the easiest creatures to summon. It turns out that sages summon them in order to trick them into patrolling dungeons. They do this by using heat or braziers to ‘steer’ the cube, which suggests adventurers can possibly utilise this technique.
Tame an ooze
Believe it or not, despite having an intelligence of 1, seemingly unable to ally with others and it’s preference for the dark, dank dungeons, some players have been known to tame a cube of ooze, using it as a portable rubbish remover and being fed enemy body parts. Whether your DM is open to this or not, is up to their discretion, with some opting to introduce DnD house rules to accommodate their players.
However, back in 2020, during the DnD Celebration, new familiar options were announced including the gelatinous ice cube, which sounds as adorable as it sounds.
The gelatinous ice cube is a tiny but dangerous cube (and yes, the size of an ice cube as the name suggests), but with the stats and hit points of an Oblex Spawn. As a tiny ooze, it can squeeze into narrow spaces and has Blindsight up to 60 feet, super helpful for scouting dungeons.
The history of the gelatinous cube
First Edition and Advanced DnD
The gelatinous cube made its first appearance in the original Dungeons & Dragons “white box” set back in 1974 and in its first supplement, Greyhawk (1975).
It has also appeared in the Dungeons & Dragons Basic Set (1977, 1981, 1983) as well as the Dungeons & Dragons Rules Cyclopedia (1991). But it has reared its six sticky sides in most versions and editions of the game.
In the first edition Advanced Dungeons & Dragons the yet-to-be infamous cube made its way to the Monster Manual (1977), to be further developed in Dragon #124 (August 1987). The first edition Advanced Dungeons & Dragons adventures to include gelatinous cubes as monster encounters for players was The Ruins of Andril, and was published in Dragon #81.
Original Dungeons and Dragons (ODnD)
|% in Lair||Nil|
|No. of Attacks||1|
Basic Dungeons and Dragons (Basic DnD)
|Damage||2-8 + special|
|No. Appearing||1 (1-4)|
|Save As||Fighter: 2|
Advanced Dungeons and Dragons (ADnD)
|% in Lair||Nil|
|No. of Attacks||1|
|Special Attacks||Paralyzation, surprise on 1-3|
|Special Defenses||See below|
|Magic Resistance||See below|
|Size||L (10’ cube)|
The gelatinous cube first appears in 2nd edition in the Monstrous Compendium Volume 1 (1989) which was republished in the Monstrous Manual (1993)
Dungeons and Dragons 2e (DnD 2e)
|No. of Attacks||1|
|Special Attacks||Paralyzation, surprise|
|Special Defenses||See below|
|Size||L (10’ cube)|
DnD (3e & 3.5e)
It appears in 3rd edition of the Monster Manual (2000/2003). From 3e to 3.5e it goes from being a huge ooze to a large ooze, despite its size (10ft cube) never changing.
Dungeon and Dragons 3e and 3.5e (DnD 3e & 3.5e)
|Hit Dice||4d10+32 (54 hp)|
|Speed||15ft. (3 squares)|
|Armor Class||4 (-1 size, -5 Dex), touch 4, flat-footed 4|
|Attacks||Slam +2 melee (1d6 plus 1d6 acid)|
|Full Attack||Slam +2 melee (1d6 plus 1d6 acid)|
|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|
|Treasure||1/10th coins, 50% goods (no non-metal or non-stone), 50% item (no non-metal or non-stone)|
|Advancement||5-12 HD (Huge); 13-24 HD (Gargantuan)|
Yet again, our ooze cube makes its way into 4th edition of the Monster Manual (2008) and appears again in the supplement, Monster Vault (2010).
Dungeon and Dragons 4e (DnD 4e)
|Senses||Perception +3; tremorsense 5|
|HP||152; Bloodied 76|
|Speed||3; also see engulf|
|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 an 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.|
As ever, the gelatinous cube appears in the first edition of 5e’s Monster Manual (2014). Thus cementing how iconic this monster is especially when you consider its lore has been so consistent. Much of the information in 5e is taken from past Monster Manuals.
Dungeons and Dragons 5e (DnD 5e)
|Hit points||84 (8d10+40)|
|CON||20 (+5 )|
|Condition Immunities||blinded, charmed, deafened, exhaustion, frightened, prone|
|Senses||blindsight 60 ft. (blind beyond this radius), passive Perception 8|
|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 of the 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.|
There is no DnD without the gelatinous cube
The fact that this six-sided ooze monster has been in every first edition iteration of the Monster Manuals is a testament to how beloved it is. Not particularly menacing for a high-level party once you know how to deal with them, but for a low-level party this is not a jelly to be trifled with (…sorry). No matter the encounter, players and DMs always have a good anecdotal story or tale about a gelatinous cube.
Is it even DnD without a gelatinous cube? You could argue that this ooze is the glue that holds the game together.
Appearances outside of dungeons
Gelatinous cubes have made their way into more than just dungeons. They’ve been in films, TV shows, video games and even in bars of soap (no, really).
- The TV series Adventure Time by Pendleton Ward
- Pixar Animation Studios 2020 release, Onward
- The NetHack video game
- Baldur’s Gate: Dark Alliance
- The 2022 Dungeons & Dragons: Honor Among Thieves film
- A film release action figure produced by Hasbro to coincide with Honor Among Thieves
- Magic the Gathering card game
- Bars of gelatinous cube soap