A Flumph Interrupted

The following one-shot campaign was created after the party inadvertently fell into a portal, as this presented an opportunity for a guest DM to run a quick and distinct session. My intention for the adventure was to target specific party weaknesses, specifically:

  • Casters spending all their spell slots too quickly
  • Tanks always rushing in
  • Bear barbarian not being resistant to psychic damage

As such, the adventure is designed to troll melee attackers and tempt casters to waste their slots on low-level creatures before facing the final battles. There should be no long rests.


The adventure is scaled for a party of level 5-7 and should take about 4 hours to play.

The plot has incorporates the following literary tropes:

First, the Escort Mission component has the party protecting a lone and vulnerable flumph. The party should truly care for this flumph, as flumphs are fragile and benevolent creatures. We want to instill a sense of trust and guardianship in our party, because at the end of the adventure, we’re going to kill off this poor creature.

Second, the A Wolf in Sheep's Clothing component has a death slaad hiding (i.e., shapeshifted) amongst a group of prisoners. The Slaadi may be seen an inter-planar terrorists who propagate their race by invading other planes and using humanoids as hosts for their eggs.

Finally, the Mad Scientist component sets the scene. Unfortunately, the party has awoken in a demiplane run by a rogue mind flayer arcanist. This mind flayer uses this plane as a transport hub for its experimental resources (e.g., humanoids and creatures). The party will need to attack the mind flayer’s base of operations to get access to its portal room in order to escape.


The following assumes the party has previously fell into a portal.

You wake to find yourselves each alone in a small, dark nook. The dark and cold stone surface surround you, just inches from your body and head. Peering down towards your feet, you can see faint glimmers of light. You wiggle your way out of the nook to find yourself in what appears to be a mortuary with a single glowing magical source of light. Looking around, you see the rest of your party also climbing down from their respective nooks.

As you stand in the chamber, you hear a soft voice in your head.

Welcome lost ones.

From a dark corner, a disfigured and vile looking creature (mindwitness), floating in the air, approaches you.

Mindwitnesses are telepathic hubs that serve other psionic creatures (e.g., mind flayers or flumphs). They are not necessarily evil, but rather follow their master.

Fear us not, lost ones. For you see there was an energetic disturbance and you all fell out of a temporary portal. As you were all unconscious, we brought you here to rest. Now that you are awake, please follow us to the Great Hall.

The Great Hall

The Great Hall is a massive cavern filled with glowing mushrooms and well-crafted stonework. The cavern encompasses the area far beyond comprehension. In what seems to be the center of the cavern, a large glowing orb, similar to a sun, floats above, providing a magical warmth to all that sit in its light.

Under the glowing orb, several creatures (flumphs) may be seen basking in the light.

These are certainly strange times. We assume that you would like to return home? Unfortunately, you have come to a terrible place. For this place was created by the illithids, or as you may call them, mind flayers. We are currently hidden below a fortress, close enough for us to feed, but far enough that they do not bother with our kind. Within their fortress lies a great portal. This place acts as a transportation hub for their slaves, thralls, and resources. If you wish to return home, I am afraid that is the only way out.

This is where we want to instill a sense of gratitude towards the flumphs.

Regardless, lost ones, we have taken the liberty of cleaning your equipment, it was quite filthy. Come, let us provide you with nourishment.

Flumphs communicate telepathically. Though they resemble jellyfish, flumphs are sentient beings of great intelligence and wisdom, possessing advanced knowledge of religion, philosophy, mathematics, and countless other subjects. Flumphs live in complex and organized groups called cloisters, within which each flumph has a place and purpose. Flumphs are sensitive to the emotional states of nearby creatures. If a creature’s thoughts suggest goodness, a flumph seeks that creature out. When facing creatures that exude evil, a flumph flees. Flumphs feed by siphoning mental energy from psionic creatures, and they can be found lurking near communities of other psionics.


As you relax and unwind with these gentle creatures, under the glowing orb, there is a sudden dark silence. Then, a piercing migraine overtakes your mind and you hear a voice:

Time for you to stop hiding.

An explosion rips through the great hall. The beautiful glowing orb crashes to the ground, its shards shattered but still glowing.

DEX saving throw (DC10) or receive 1d4 piercing damage from shards

Breaches into the cavern are formed where the orb once was. The mindwitness is crushed by the falling orb.

From above, floating entities descend (grell), grapple the kind and loving flumphs and carry their bodies away. Other flumphs attempt to flee through the breaches in the wall, but are consumed by a ghastly creatures that ambush their escape. A single flumph remains, having managed to dodge the tentacles of a floating monster, scared, and flees into a narrow passage in a far wall.

The party should follow the flumph into the passage to protect it.

Save the Lone Flumph

The narrow passage leads to a dark, rocky crevasse with sheer rock walls. The party catches up with the lone flumph who is very scared. Behind and ahead, the passage is now blocked by two gibbering mouthers A grell descends from above.

The two gibbering mouthers are the real threat of this encounter and are designed to troll melee attackers. As they have terrible movement speed, make sure to draw a narrow passage to prevent the party from kiting the enemies.

Loot Quantity Description Unit Value
Hematite 1 Opaque gray-black 10 gp
Malachite 1 Opaque striated light and dark green 10 gp

To the Surface

The lone flumph turns blue. In sadness he says:

My cloister is now dead, I must find a new home. Please, allow me to guide you to the exit of this realm. You may call me Beta.

As the party ventures through the crevasse, wisps of faint purple glow can be seen throughout the air. An upwards slope towards an exit can be seen up ahead. After exiting, you are standing on stony ground with scattered glowing mushrooms. Above you is just void, the infinite. No stars, no light, no distance, just pure blackness.

An invisible gray slaad is now following the group. It is the real reason for these attacks and explosions. Coincidently, the party arrived in the plane while the slaad were mounting a cloak-and-dagger attack on the mind flayer. Having learned about the party’s arrival, the slaad now want to use them as pawns and decoys.

Looking ahead, you can make out what appears to be a sort of pyramidal structure outlined in glowing orbs. Elsewhere along what you conceive to be the horizon, there is just emptiness.

Beta reveals that the pyramid is the base of operations for a deviant illith and that the portal is inside.

In the distance, towards the structure, you hear screams and shouts…

The Prison

You approach what appears to be a mix between a shipping port and a prison camp. Rows upon rows of monolithic cages, like black stone claws piercing from the ground. Many of the cages house monstrous entities, many of which you do not recognize and cannot even begin to comprehend.

The screams and shouts are coming from a prison cell ahead. You see a group of three humans.

One man approaches the bars. Brown, shaggy hair almost fully covers a strong, warm face. Glistening black eyes, set sunken within their sockets. He stands oddly among others, despite his strong frame.

Thank the heavens! I’m Orion Faley and you must help us! There were large explosions! Some of the cages nearby were blown open and some of the monsters escaped into the wild! They were vile creatures and headed in your direction. Are they dead?

Orion is actually a shapeshifted death slaad and the leader of the offensive operation. He can communicate properly due to gray and death slaads innately having the tongues spell.

Around you, you can see cages of gibbering mouthers, grells, quaggoths, and troglodytes. Nearby you see some broken cages. In one of the cages, the charred remains of what look like human corpses are all that is left behind.

The slaad had blown up the cages, releasing the monsters to attack the flumph to draw the party out of hiding.

The other prisoners are shouting:

Fireballs rained down and blew up the cages! We are trapped! We were kidnapped from our homes and transported here! We will be devoured! We were transported here by some sort of magic! In that structure is where we arrived!

Use this opportunity to troll your party with low-CR creatures (e.g., quaggoths) breaking free from cages (e.g., if they cause too much noise while freeing the prisoners).

Perception (DC10) to notice the human cages have no top, just spikes. Climbing up and dropping rope or levitating the prisoners is a valid (and quiet) solution.

Orion after being freed gives the party 1d4 healing potions:

You look hurt, let me repay you. This is all I have left. Please let us follow you, we must escape this place.

Loot Quantity Description Unit Value
Turquoise 2 Opaque light blue-green 10 gp

The Pyramid

The party ventures towards the pyramid, escorting beta and the prisoners. A long, path lined with obelisks (topped with magical light sources) leads towards the entrance.

Entrance Corridor

The party follows the path toward what looks to be an entrance arch.

Mind flayers guard their entrances with illusions.

The entrance arch is currently under the effects of major image and hides two ogres at the ready with javelins.

Cleansing Chambers

Inside the structure, massive glowing crystal orbs are mounted on onyx columns and light up the entire corridor and engulf everything in a flickering radiance.

Little alcoves are found along this corridor where flesh, hair, and equipment is piled into the corners.

Freshly captured victims are processed in the cleansing chambers. Their gear is removed and either destroyed or kept if it is of interest, their hair is shaved to prevent parasites, and any sickly ones are disposed of.

Loot Quantity Description Unit Value
Gold locket 1 Painted portrait inside 25 gp
Dagger 1 Melee weapon (simple, dagger) 2 gp
Manacles 1 Metal restraints 2 gp
Bloodstone 1 Opaque dark gray with red flecks 50 gp

Brain Chamber/Library

You enter a large room. A humongous crystal hangs from the oblique ceiling. In the flickering light, you see rows of finely cut crystals in individual sockets along the walls.

Closer inspection reveals that these crystals are not empty, nor are they purely solid. They contain what appears to be a liquid and inside, a floating brain.

At the center of the room lies a throne-like altar whereupon lies a dissected human body.

Loot Quantity Description Unit Value
Illith Book of Human Anatomy and Physiology 1 Written in Qualith; contains the following spells: Confusion (4th level enchantment), Ray of Enfeeblement (2nd level necromancy) 50 gp

A corridor exits this room.

Transformation and Experimentation Chamber

The corridor enters into a large chamber with several large crystalline vats filled with mysterious liquid and wretched monstrous forms.

The transformation chamber contains a number of small cells. The subjects of promising experiments are kept here, bombarded with psionic energy in an effort to warp their physical development. Most creatures that undergo this process are turned into twisted, crippled wretches, but a few emerge stronger and tougher than before.

A voice booms in your heads

Who are you! Why have you disturbed my studies! Regardless, more fresh brains, thank you for delivering yourselves to me!

At the opposite end of the room, a humanoid looking squid (mind flayer arcanist) appears. Several thralls (2x troglodytes) burst from the vats.

Loot Quantity Description Unit Value
Onyx 10 Opaque bands of pure black 50 gp
Potion of Healing 2 Regain hit points when you drink this potion 50 gp
Potion of Greater Healing 1 Regain hit points when you drink this potion 100 gp

Teleportation Room

Following the battle with the rogue illith, Orion shouts “you did it!” and leads the way to the teleportation room.

Six great obsidian platform are aligned throughout the room. Mysterious glyphs are carved into the stone and glow with a light blue hue.

At the center of the platforms appear to be energetic rifts, similar to the one that brought you here.

At the back of the room is a large black altar.

Orion goes to look at the portals. He looks back at your party and says:

If a single illith sees you, they all see you. One mind. One nasty, suspicious mind. But they will not recognize me… It was quite the coincidence how we all arrived here at the same time.

Orion walks to the altar and picks up sets of tuning forks. He takes out and taps each fork and purple energy floats from the portals to the forks as the frequency of the forks change. The sound becomes steady and the forks ring throughout the chamber.

But, this is now my dominion, my stepping stone to the other worlds. My original plan was to overtake this portal hub through subterfuge. But alas I found you, or rather, the feeble jellyfish found you. It was quite trivial you see, faking imprisonment, blowing open the jellyfish’s hideout and getting you to do my dirty work.

Orion stares at Beta. Beta turns red and backs away.

Passive perception (DC14) to notice that there is now an extra human with the prisoners (shapeshifted gray slaad).

Orion shapeshifts into a large beast (slaad form).

Now, you have my permission to die. Kill them.

The human prisoners begin to scream.

In the chaos, the extra human draws a greatsword and cuts through Beta, instantly killing the kind, loving, helpful creature.

Orian simple vanishes (plane shift).

The extra human reverts to its grey slaad form and attacks.

The remaining human prisoners will act erratically trying to run away. They will be collateral damage.

Label the portals 1-6. Any creature that jumps into a portal will reappear randomly (d6) beside another portal.

Loot Quantity Description Unit Value
Mysterious tuning fork 1 Re-tunes the portals in the room to a random location 250 gp
Wrath of the Slaadi 1 Ancient symbols are engraved on the blade, which is supposed to contain a hidden power. The markings suggest that this item is linked to a deed of great evil such as a massacre.

Greatsword +1: You gain a +1 bonus to attack and damage rolls made with this magic weapon.

Modron Sentinel (boon; requires attunement; identifiable): This item glows faintly when Modrons are within 120 feet of it.

Curse of Vengence (curse; requires attunement; unidentifiable): This sword is cursed and possessed by a vengeful spirit. Becoming attuned to it extends the curse to you. As long as you remain cursed, you are unwilling to part with the sword, keeping it on your person at all times. While attuned to this weapon, you have disadvantage on attack rolls made with weapons other than this one. In addition, while the sword is on your person, you must succeed on a DC 15 Wisdom saving throw whenever you take damage in combat. On a failed save you must attack the creature that damaged you until you drop to 0 hit points or it does, or until you can’t reach the creature to make a melee attack against it. You can break the curse in the usual ways. Alternatively, casting banishment on the sword forces the vengeful spirit to leave it. The sword then becomes a +1 weapon with no other properties.
250 gp