blindsight 60 ft. (blind beyond this radius), passive Perception 8
Languages
—
Traits
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 15 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.
Actions
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.
How gelatinous cubes fight
A gelatinous cube is a 10-foot block of transparent jelly that slides through dungeon corridors, filling them wall to wall. Unless it moves or attacks, spotting it takes a DC 15 Wisdom (Perception) check, and a creature that walks into it unaware is surprised.
Its real attack is Engulf. It moves into creatures’ spaces, and each one must make a DC 12 Dexterity save or be swallowed. An engulfed creature takes 3d6 acid immediately, then 6d6 (21 on average) at the start of each of the cube’s turns. It can’t breathe, it’s restrained, and it has total cover, so its allies can’t attack past the cube to help. It can hold up to four Medium creatures at once.
Running a gelatinous cube at the table
Fill a corridor. In a 10-foot-wide passage, the party can’t go around it, and the cube can advance and engulf everyone in front.
Let it come to them. A motionless, transparent cube around a corner is an ambush in itself.
Keep engulfed victims inside. Its pseudopod is weak; the 6d6 acid each turn is what kills.
Put treasure in it. Monster Manual lore has cubes carrying undigested coins, bones and metal gear inside them. It’s a good way to hide a key or a lost adventurer’s sword.
Common questions
How do you see a gelatinous cube?
If it hasn’t moved or attacked, it takes a successful DC 15 Wisdom (Perception) check. Once it moves or attacks, it’s obvious.
How do you escape from a gelatinous cube?
Use your action to make a DC 12 Strength check. On a success you get out and move to a space within 5 feet of the cube.
How do I pull an ally out of a gelatinous cube?
Stand within 5 feet and use your action for a DC 12 Strength check. It works, but you take 3d6 acid damage for reaching in.
Can I avoid being engulfed?
When the cube enters your space you make a DC 12 Dexterity save. On a success you can choose to be pushed 5 feet back or to the side instead.
Can an engulfed creature fight back from inside?
Yes. An engulfed creature is restrained, so it attacks with disadvantage, but it can attack the cube or cast spells. Creatures outside can’t target anyone inside, since they have total cover.
How dangerous is a gelatinous cube?
It’s CR 2, worth 450 XP. For four characters, the Dungeon Master’s Guide’s encounter math makes it Deadly at 1st level, Medium at 2nd and Easy at 3rd, though a surprise engulf can still kill a low-level character.
CR 5. Another motionless ambusher that drags victims in.
How many gelatinous cubes for a fight?
A gelatinous cube is worth 450 XP. Using the 2024 encounter budgets (SRD 5.2), this is how many gelatinous cubes fit each difficulty for a party of four characters of the same level. A dash means even one would be over the budget.
Party level
Low
Moderate
High
2nd
—
1
1
3rd
1
2
3
4th
2
3
4
5th
4
6
9
6th
5
8
12
7th
6
11
12+
8th
8
12+
12+
9th
11
12+
12+
Budgets add up every monster’s XP, so you can swap some for other creatures of the same total. Try other party sizes and mixes in the encounter calculator.
How the gelatinous cube compares at CR 2
Against the 42 other challenge 2 monsters in the SRD 5.1, the gelatinous cube has more hit points than 41 of them, which makes it one of the toughest at its CR. See every CR 2 monster.
Statistic
Gelatinous Cube
CR 2 average
Armor Class
6
13.1
Hit points
84
46
Best attack bonus
+4
+5
Best save DC
12
12
Gelatinous Cube 2024 stat block
The 2024 Monster Manual revised the gelatinous cube, and the SRD 5.2 carries the new stat block. What changed:
Ooze Cube. The cube fills its entire space and is transparent. Other creatures can enter that 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 have Total Cover, and the cube can hold one Large creature or up to four Medium or Small creatures inside itself at a time. As an action, a creature within 5 feet of the cube can pull a creature or an object out of the cube by succeeding on a DC 12 Strength (Athletics) check, and the puller takes 10 (3d6) Acid damage.
Transparent. Even when the cube is in plain sight, a creature must succeed on a DC 15 Wisdom (Perception) check to notice the cube if the creature hasn’t witnessed the cube move or otherwise act.
Engulf. The cube moves up to its Speed without provoking Opportunity Attacks. The cube can move through the spaces of Large or smaller creatures if it has room inside itself to contain them (see the Ooze Cube trait). Dexterity Saving Throw: DC 12, each creature whose space the cube enters for the first time during this move. Failure: 10 (3d6) Acid damage, and the target is engulfed. An engulfed target is suffocating, can’t cast spells with a Verbal component, has the Restrained condition, and takes 10 (3d6) Acid damage at the start of each of the cube’s turns. When the cube moves, the engulfed target moves with it. An engulfed target can try to escape by taking an action to make a DC 12 Strength (Athletics) check. On a successful check, the target escapes and enters the nearest unoccupied space. Success: Half damage, and the target moves to an unoccupied space within 5 feet of the cube. If there is no unoccupied space, the target fails the save instead.
