Illustration Xan Drake

Gelatinous Cube-Mother

xandrakeart
Challenge 18
(20,000 XP)
Robinloft Estimated CR 17
Gargantuan ooze, unaligned
Armor Class 8
Hit Points 350 (20d20+140)
Speed 30 ft.
STR
18 (+4)
DEX
6 (-2)
CON
24 (+7)
INT
2 (-4)
WIS
8 (-1)
CHA
2 (-4)
Saving Throws Str +10, Con +13
Skills —
Damage Resistances bludgeoning, piercing, slashing
Damage Immunities acid
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, prone
Senses blindsight 60 ft. (blind beyond this radius), passive Perception 9
Languages —
Environments
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 14 Strength check, and the creature making the attempt takes 24 (7d6) acid damage.

The cube can only hold as many creatures as will fit inside its space at one time (e.g. up to four Large creatures or up to sixteen Medium or smaller creatures).
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: +10 to hit, reach 15 ft., one creature. Hit: 24 (7d6) acid damage.
Engulf.

The cube moves up to its speed. While doing so, it can enter Gargantuan or smaller creatures’ spaces. Whenever the cube enters a creature’s space, the creature must make a DC 15 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 24 (7d6) acid damage and is engulfed. The engulfed creature can’t breathe, is restrained, and takes 35 (10d6) 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 14 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the cube.
Spawn.

The cube splits off some of its mass to create a regular Gelatinous Cube within 5 feet of itself. The cube’s hit points are reduced by 84 (8d10 + 40) and the same value becomes the hit points of the newly created Gelatinous Cube.

Legendary Actions

The cube-mother can take 3 legendary actions choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The cube-mother regains spent legendary actions at the start of its turn.
Digest. The cube hastens its digestive process. Every creature currently engulfed by the cube takes 35 (10d6) acid damage.
Ooze Bomb. The cube spits out some of its mass to splash an area with corrosive slime. The cube chooses a point within 60 ft. and all creatures within a 10 ft. circle around that point must succeed on a DC 13 Dexterity saving throw or take 17 (5d6) acid damage.
Absorb (Costs 2 Actions). The cube absorbs a nearby gelatinous cube, increasing its own hit points by the remaining hit points of the absorbed cube.

Gelatinous Cube-Mother

Not yet described

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