The Caverns of Ooze
A One-Page Dungeon Adventure
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Plop… Plop… Thud.
Benvido stepped past the enormous stone door and paused. Xacobe followed.
They both stood staring into the passage before them. It yawned like a jagged maw in the earth, exhaling damp, fetid breath. Beyond: a shadowy curve lead deeper into the cavern. The strange green glow that had haunted their dreams pulsed faintly from the depths, illuminating the rough stone walls in an otherworldly shimmer.
“I have a bad feeling about this…” muttered Benvido. With a deep frown on his weathered face, he eased into the tunnel another step or two. The shoulders of his hauberk gleamed amber-gold in the weak torch light.
“Agreed.” Xacobe’s gruff voice returned in wet echoes. “But… there’s only one way to discover what’s down there.” She slowly slid her sword from its sheath.
With a final glance at one another, they pushed forward.
The darkness swallowed them whole, save for the dim bioluminescence that oozed from cracks in the rock. Stalactites, slick and glistening, loomed overhead like jagged teeth, while the floor was uneven, damp, and… seemed to writhe.
A sound drifted through the cavern. Plop… plop… thud.
Something wet had fallen nearby.
“What was that?” Xacobe growled. She stood, frozen, focusing on the sound.
Benvido took another step forward. Squelch. The ground beneath his boot felt slick. He raised his torch, but the firelight barely cut through the thickening green haze.
Then, as their eyes adjusted, they looked up.
And they saw them—undulating slugs—clinging to every surface, dangling from the ceiling with strands of thin, shimmering slime. Their bloated bodies pulsed and contracted as they moved, nibbled, searched.
It was an underground orchard bursting with sickening fruits.
Plop… plop… thud.
A drop of ooze fell from the ceiling, nearly missing Xacobe’s cloak.
Plop… Then another. Somewhere in the dark.
Plop… plop… plop…
The two adventurers began to take slow, careful steps backwards. But it was too late.
Like gooey rain, the slugs began to fall.
A One-Page Dungeon
The Caverns of Ooze is my first attempt at a one-shot adventure contained completely on one printable page.
It's designed for Dungeons & Dragons 5e (3-4 level one characters), but it could easily be adapted for any table-top roleplaying game.
Try it out! Use the text here or visit my Itch.io page and download the Caverns of Ooze pdf.
Will you uncover the truth of the Slug Master’s exile?
Can you claim the powerful Necro Stone without dooming yourselves?
Or will the crawling horrors lurking in the dark consume you whole?
The Story Begins…
As night falls, a strange green light fills the Western Horizon—dimly illuminating the tree-covered hills, merely a few hours walk through the wild. It seems only a curiosity… until you each experience similar dreams.
D6 Dreams
A stone door opens, revealing a comforting green glow.
A river of green slime bubbles from a mountain top.
Thunderous Green Laughter! Voices filling a cavern with ancient song… green light seeps into the edges of vision.
A green lake stretches out into the darkness… towards a large glowing emerald
Green eyes grow closer, whispering, “Free Meeee!”
General Imagery
• Stalactites of various size cling to the ceiling.
• Eerie green radiance fills the dark.
• A distant “drip…thud!” like jelly striking ground.
• Earthy fumes… like rotting leaves linger in the air.
• You feel as if you’re being watched… from above?
Necro Slugs!
Pear-sized lumps of organic sludge hang by thin strands of slime—from every cranny of the cavern ceiling—emitting a dim green bioluminescence.
When The Pc’s Enter a Zone… Roll a d6
1-4 = Necrotic Plop!
When the PCs enter the zone, several slugs fall from the cavern ceiling. The strands of suspension slime pull apart… and re-lease. Each PC must make a DEX Save vs. DC 12 or… Plop!
Fail = hit with a slug and take 1d4 + 1 Necrotic Damage.
Save = the slug splats to the ground and begins to slide back to the wall and ooze upwards.
5-6 = Curious Tracks
Small tracks can be seen covering the floor…
DC 10 Survival: leaving the caverns?
DC 14 Nature: crab-like? Spider-like?
Pools of Goo
Green, bioluminescent pools of viscous liquid—like slightly warmed snot—are throughout the caverns.
DC 10 Perception: Every few moments, a Necro Slug will emerge from the edge and slime towards the nearest wall.
Necrotic Poison: The goo causes 1d4+ 1 Necrotic Damage on touch (even through armor/clothing)!
Room 1. Invitation?
An Ancient Stone Door waits just inches ajar. Its deliberate design is a strong contrast to the natural cavern.
DC 12 Athletics: The door opens enough—only a sliver of shadow.
DC 12 Investigation: Disturbed dust and gravel. Was the door recently opened?
Room 2. Blocked by Goo
A shallow Pool of Goo fills the path.
DC 12 Athletics: Jump?
DC 12 Acrobatics: Shimmy past it?
Room 3. Natural Rock Stairs
The cavern floor slopes down. There are steps here formed by layers of rock.
DC 10 Investigation: Some tool marks. These steps were crafted by intelligent hands.
Room 4-5. The History of Ooze
The far wall of this cavern is nearly covered, bottom to top, by a pair of masterfully carved murals.
Room 4. “The Arrival!” Mural
A skeletal figure, smiling, is held aloft by a spider-like palanquin. Humanoid figures surround him with their arms raised in supplication. Steps rise up behind the figure, into the sky, and connect to a dotted sphere hovering in the clouds.
Room 5. “The Rebellion!” Mural
A skeletal figure, in expansive, flowing robes shields its face from rays of sunlight. One leg stands in a stone-shaped, man-sized prison cell. Humanoid figures crowd intensely around. All wear angry faces, waving fists in the air. Little spider-like creatures climb on the edges.
Room 6. Flooded Cave
A large, hip-deep Pool of Goo fills this area. How will the heroes cross?
Room 7. Dimensional Prison
Near the middle of this cavern stands a man-sized boulder, perfectly smoothed. A depression just large enough for the Necro Stone is its only feature. The rock material is mostly transparent, and a figure can be seen within… The Slug Master.
Room 8. Stalagmite Island
In the dead-center of the Pool of Goo (about 15’ from the edges), a stalagmite rises up, surrounded by the strange green liquid. Resting in a carved notch on the top of the pedestal (as if on display) sits the Necro Stone.
The Necro Stone
A square-cut luminous emerald the size of a walnut, it opens the Dimensional Prison.
Blessing! While holding the stone in one hand, the user gains Damage Immunity: Necrotic.
Curse! After each use, the wielder must make a CON Save vs. 10 or emit a green bioluminescence like the Necro Slugs (Disadvantage on Stealth) 1d10 hours.
The Slug Master
Use the Wight stat block found in the D&D 5e Basic Rules (or (free from D&D Beyond) with one exception: when slain by Life Drain, a victim becomes 1d10 Necro Slugs (not a zombie).
“Ah! Yes! My heroes have arrived to free me from this torment!”
An inter-dimensional being who thrives on the life-force of mortals, the Slug Master appears thin and frail—weak, a victim, begging for help and offering rewards. His form is swallowed by flowing, purple robes. His voice is old, and it carries an unearthly echo—projecting sound both in the cavern and the mind.
DC 14 Intuition: Do. Not. Trust. Him.
DC 16 Perception: long-sword beneath his robes!
Free the Slug Master…
He drops the helpless victim guise. He attacks! The Slug Master wields an ancient longsword (worth 50 gp), but he strikes with Life Drain whenever possible.
Slug Master Stats
Medium Undead, Neutral Evil
STR: 15 (+2) | DEX: 14 (+2) | CON: 16 (+3) | INT: 10 (+0) | WIS: 13 (+1) | CHA: 15 (+2)
Armor Class 14 (studded leather)
Hit Points 45 (6d8 + 18)
Speed 30 ft.
Skills: Perception +3, Stealth +4
Damage Resistances: Necrotic; Bludgeoning, Piercing, and Slashing from Nonmagical Attacks that aren't Silvered
Damage Immunities Poison
Condition Immunities Exhaustion, Poisoned
Senses: Darkvision 60 ft., Passive Perception 13
Challenge 3 (700 XP)
Proficiency Bonus +2
Traits
Sunlight Sensitivity: While in sunlight, the wight has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Actions
Multi-Attack: The wight makes two longsword attacks. It can use its Life Drain in place of one longsword attack.
Life Drain: Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 5 (1d6 + 2) necrotic damage. The target must succeed on a DC 13 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.
A humanoid slain by this attack rises 24 hours later as a zombie under the wight's control, unless the humanoid is restored to life or its body is destroyed. The wight can have no more than twelve zombies under its control at one time. immediately collapses and transforms into a pile of d10 Necro Slugs.
Longsword: Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) slashing damage, or 7 (1d10 + 2) slashing damage if used with two hands.
“Attack! My Pets!”
The Slug Master calls the Necro Slugs throughout the caverns to “Rise!” They trans-form into Necro Crawlers.
He will activate the “Attack! My Pets!” command if…
The PCs refuse to free the Slug Master.
The PCs flee (the Slug Master won’t pursue).
The Slug master is defeated (these are his last words).
Necro Crawlers
URRGH! The hundreds of weird slugs covering the ceiling were actually larvae…
The PCs watch in horror as the things sprout thin, insectoid legs, stretch craggy mandibles… and hatch! (Necro Crawlers made the Curious Tracks.) They swarm the heroes!
Necro Bite: +3 to Hit | 1d4 +1 Necrotic Damage
Swarm: Each time the PCs enter a new zone, roll d12 +6. The result is the number of Necro Crawlers that hatch before their eyes… and attack! With 3 or less Crawlers left in a zone, roll again!
Get ‘Em Off Me! If the PCs successfully hit the swarming Necro Crawlers (AC 8), every point of damage destroys one of the creatures.
The Crawlers will pursue the heroes throughout the cavern and even beyond!
The End?
Can the PCs escape with the Necro Stone… and their lives?
Bonus XP if the PCs manage to close the cavern entrance!
Author’s Notes
Recently
posted a pretty helpful post on dungeon design:
His "ABC Method" worksheet provides a structured approach, breaking dungeon creation into three phases: Anchoring, Backstory, and Curating. It’s worth checking out (and it’s free).
After reading this piece, I thought about The Caverns of Ooze. And I felt confident that it fulfilled Nate’s dungeon creation must-haves.
Anchoring: There’s an established theme of corruption (and maybe transformation).
Backstory: The Slug Master, an interdimensional entity, was imprisoned here by the culture he once ruled. The dungeon serves as both a prison and a breeding ground for his Necro Slugs.
Curate: The Caverns are broken down into several zones that support the theme (pools of necrotic—or corrupting—goo, murals provide backstory, and the final encounter with the deceptive Slug Master offers both social interaction and combat.
His post inspired me to finally get the Caverns of Ooze out into the wild (well… world wild web, anyway).
Give It a (One) Shot
Although I’m just now releasing the Caverns of Ooze as a published adventure, I’ve run this one-shot for players many, many times.
I realize it could use a few improvements:
Bring All The Stats: The adventure leans hard on Strength Dexterity, and overall physical/combat prowess. It would feel more well-rounded (and allow a time to shine for all PCs) if it had encounters that required a decent Charisma, Intelligence, or Wisdom score.
Provide Alternative Solutions: Making space for a non-combat resolution (something like resealing the Slug Master, for instance) could offer more player choices. As it is now, most players eventually come to one conclusion: run!
Expanded Rewards: The one-shot definitely needs more thematic loot (maybe… armor resistant to necrotic damage? A necrotic sword? The Slug Master as warlock patron?). This might give players more incentive to explore beyond the Necro Stone (which might not help them beyond the Caverns).
When you’re trying to fit everything on one printable page, however, not everything is gonna fit. I’m Ok with that.
Overall, it works well as a one-shot adventure.
Try out the Caverns of Ooze at your table!
I’d love to hear what happens!
What do you think is important for a great one-shot adventure?
This sounds like a lot of gross oozy fun! I think I can fit this in for some solo play in Shadowdark.
This is super cool. I love the short story introduction, it's very evocative.