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  • Medley of Deadly Jelly – Spooky Slime Encounter for D&D 5e
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A horror-themed ooze encounter for parties of 3rd-level or higher, with stat blocks for use in D&D 5E.

The local lord has recently been deprived of his hired wizard, who disappeared suddenly after a period of reclusion and odd behavior. The wizard’s abandoned house and belongings are now being dealt with. This led to the discovery of a strange hole that had been burned through the floor of his laboratory and descended into an ominous green glow. 

This hole is the work of a vat of experimental material being left in the house. Its owner’s hasty exit resulted in the container of failed tests being neglected for enough time to develop into something new. Whatever was born from the vat burned and tunneled its way downwards. It found a small, watery cavern, in which it now resides and continues to evolve.

This situation has become a problem for the Gambren Family Cleaners company. They have been hired to make the house presentable, with a deadline of the next day when the noble wishes to post the property for sale again. This pressure worsened when their initial foray into the house ended with their newest employee, a young elven lad, having been dragged down the pit and disappearing into the ominously lit darkness. Naturally, the Gambrens wish to avoid further casualties. With their time running out, the twins rush around town searching for able-bodied adventurers to aid in a dangerous task. They require capable fighters to descend into the hole and eliminate whatever is down there in exchange for a portion of the Gambrens’ pay. Anyone that is willing to accept the task is to meet them at sundown at the now-empty house of Baltazar Bridgers.

The story of this encounter connects to those of our previous two ooze encounters. Be sure to check them out to learn more about Baltazar Bridgers and his creations…

Crime and Slime - Banner

Crime and Slime

Strange oozes have filled a thief hideout in the city sewers. What can these new slimes do, and where have the thieves gone?

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Ooze on the Loose

A reclusive wizard’s basement ritual room is filled with experimental, elemental oozes that must be dealt with before they escape.

Maya and Valter Gambren

A pair of dwarves enter, one man and one woman with strikingly similar features to each other and the same auburn hair. They pose upright and move with their chins raised. But you watch as they walk and notice their frazzled hair, a sheen of sweat on their brows, and an unnerved quickness in their step.

The Gambren twins are the current inheritors of Gambren Family Cleaners. They are a meticulous and canny pair with no shortage of mercantile experience between them. While this is a strength for their business, it has led to many seeing them with disdain due to their attitudes towards their competitors, detractors, and even employees. 

Their current stress has dented the twins’ acumen. They are desperate for their reputation, and therefore their coffers, to remain intact and thus urgently require the assistance of adventurers. They are less tactful and attempt to hurry through conversation. Despite offering an initially meager amount of gold for the job, they can be quickly convinced to raise the fare, much to their visible frustration. Similarly, the two are unlikely to mention the lost employee, though they may do so accidentally if questioned. 

The Gambrens are overjoyed if the party accepts, though they remain just as impatient. They are eager to rush straight to the house, where they encourage the group to venture inside while they await news of it being safe. Once the task is complete, the Gambrens hand over the promised gold, expressing their appreciation with only a hint of annoyance, before shooing the party away. The Gambrens make no mention of receiving help when they later report back to the noble.

Extracting explanations. Though the Gambrens are initially vague about the state of the house, they can be pressed for more information. If the party asks specifically about what the danger in the house is, the twins accidentally mention the loss of their employee, though they downplay the significance of his likely death. A character that inquires further can make a DC 14 Charisma (Persuasion) check, or another appropriate skill check, to have the Gambrens reveal more. On a success, the cleaners recall a distinctly wet sound when their employee was taken. If the character rolled a 16 or higher, Valter Gambren also mentions returning to the house afterward to recover their tools. He reluctantly admits to hearing odd sounds echoing from the hole, which he describes as being similar to moans and failing speech.

The Acid Cave

The shaft descends through rough earth, then to stone, as the green light below grows closer. Descending also causes the smell to worsen, an off-putting aroma turning into an acrid, venomous stench that sizzles the nostrils.

The tunnel expands suddenly where it appears to have met an existing cavern. A central chamber branches into other pathways and smaller openings, with stalactites and columns forming from the ceiling. The ground, meanwhile, holds large pools of liquid that glow dimly with the green you had been seeing from above. This fluid bubbles oddly, releasing similarly-colored fumes that fade into the cave’s stifling air.

In his abandoning of the house, Bridgers left behind a vat of ooze that he had been experimenting on in his private time. This ooze, which was more successful than Baltazar had realized, awakened and burned its way through the bottom of its container. It continued downwards until it fell into a cavern system, where it currently resides. 

These natural caves have only ever housed pools of collected moisture and therefore, though they were known about, they were never a problem. The recent growth of Bridgers’ experiments has changed that. The ooze has separated into many different variations, each individual slime evolving differently to the next. The worst of these were born from the unfortunate death of the Gambrens’ employee. If that were not enough, the developing oozes have also dispersed into the water, polluting it into a diluted acid.

Seared shaft. A cylindrical, vertical hole is burned through the floor of the house. The shaft has a radius of 5 feet and descends 20 feet through the earth before it reaches the ceiling of the cavern. This opening is 15 feet above the floor of the cave.

Lighting. The acidic water of the cave gives off a faint green glow, filling the chambers with dim light.

Acidic pools. The pollution of the caverns’ water has left it with mild corrosive properties. A creature that starts its turn in the liquid or that enters it for the first time on a turn takes 2 (1d4) acid damage.

Map & Asset Downloads

The cavern under Bridgers’ house is modeled after our very own Acid Cave. If you’re looking for a map for the house itself, consider using the Shanty’s upper floor or building your own with our wide array of different building assets…

Spooky Slimes

The experimental material left behind by Bridgers has gestated into new variations of ooze. Several of these were born from Baltazar’s earliest attempts at testing the limits of his creations. Others are far removed from anything their creator ever intended, having mutated from the unfortunate death of the cleaner.

Sanguine Slime

A thick glob of deep crimson roils and shifts. It slides forwards like a drop of water down a pane of glass, leaving a stained trail behind it and giving off a distinctly familiar, metallic smell.

The sanguine slime is named as such for both its blood-like appearance and its vampiric ability to absorb the life force of its victims. This side effect, in the case of other creatures, would normally only serve to extend its life in a fight. But the sanguine slime takes its regeneration a step further by growing as it heals, potentially allowing already split slimes to regrow and split again.

Corpse Ooze

An ooze of bright, almost luminescent green fills a strangely humanoid shape. Suspended in its bulbous body is an incomplete human skeleton, around which the slime’s makeshift limbs are formed. It makes unnatural, lumbering movements as if imitating a second-hand memory of whatever poor victim it now contains.

Corpse Oozes are slimes that have absorbed a singular victim and then formed themselves into its shape. They retain the creature’s skeleton in their core, with the ooze wrapping around it to imitate flesh and muscle. This does, however, tend to be hindered by the oozes’ lack of any education on the topic of biology, which only adds to its unsettling nature. Corpse oozes closely resemble undead in their abilities, with humanoid variants being similar to zombies, though their malleable, acidic form sets them apart as a unique threat.

Ghostly Cube

The cube shimmers a translucent blue-grey, fading and distorting like a desert mirage. Its body seems clouded in a spectral fog that drips off it and prevents your eyes from properly focusing on its illusive form.

Like the ghost of a gelatinous cube, the ghostly cube shares several abilities with forms of incorporeal undead. The cube can close distance by phasing through solid objects and by shifting into and out of the Ethereal Plane, avoiding anything or anyone that might attempt to slow it. Perhaps the only saving grace is that the cube does not take its consumed victims with it into the Ethereal Plane, forcing it to choose between its hunger and its own survival.

Necrotic Jelly

A glob of pure black ooze is obscured by the shadowy mist that surrounds it in shades of deep purple. It moves with unnatural smoothness and silence, creeping along the ground like a shadow given indistinct form.

The necrotic jelly is an ooze that embodies purest darkness, with abilities resembling other creatures of shadow. This includes attacks that drain its victim of their vitality, as well as being able to easily disappear into areas of darkness.


The pale red ooze appears to churn and bubble. Lumps of its surface rise and then part as if bursting in slow motion, yet the sight and sound of these bubbles are far more disturbing than expected. Each mound opens in the shape of a mouth and releases a gurgling imitation of a voice, whining in distorted agony.

Had Baltazar Bridgers ever considered the process of peer review, his attempts to give ooze the gift of speech would sure have been shot down. But he did not, and so the lyreslime was born. Similar to a gibbering mouther in its appearance, the lyreslime’s abilities are more focused and reflective of the purpose of its creation. It can mimic the sounds of animals and even humanoid speech, though these are limited by the ooze’s lack of intelligence. When under threat, the lyreslime’s mouths also make for effective weapons and its screams can disrupt attackers’ faculties.

Balancing the Oozes

The death of the Gambrens’ employee and the slimes that were born from it provide an easy starting point for choosing how many oozes to include in the encounter. His death resulted in at least one corpse ooze and one lyreslime, the latter being what Valter Gambren heard from within the hole. This starts the encounter at CR 1 1/2.

For parties above 5th-level, adding sanguine slimes and ghostly cubes can quickly raise the encounter’s challenge. Your use of the former should depend on how likely it is that the party will trigger its Split reaction. Characters that rely on lightning or slashing damage can quickly raise the sanguine slime’s effective challenge rating, which provides an interesting need for strategy but can also spiral a difficult encounter into something far more deadly.

Necrotic jellies and other weaker oozes help to fine-tune the encounter’s CR. This is helpful for parties that are 4th-level or below or for bolstering the oozes’ numbers after adding a sanguine slime or ghostly cube. You can do the same with additional corpse oozes or lyreslimes, though you may wish to include rumors of missing people around town to explain where the skeletons came from.

Here are some examples of creature choices you can use to achieve different CR values for the encounter:

CR 3 1/2: 1 corpse ooze, 1 lyreslime, 1 ghostly cube.

CR 5 1/2: 1 corpse ooze, 1 lyreslime, 1 sanguine slime.

CR 7 1/2: 1 corpse ooze, 1 lyreslime, 2 necrotic jellies, 1 sanguine slime.

CR 10: 2 corpse oozes, 2 lyreslime, 1 necrotic jelly, 1 ghostly cube, 1 sanguine slime.

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About the author

Troy McConnell

Part-time DM and author of 2-Minute Tabletop's encounters, map lore, and characters. Basically, I write about all the campaign ideas that I don't have time to run. All with the assistance of my feline familiar, Wink.

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