The Giant Rotting Dungeon

The corpse of the giant rots in the mountain range. What treasures could we find within its belly?

This is based on an image prompt I did with a few friends. The idea is we all make a dungeon based on this image (I believe this link is to the original creator: umbatman). Mine was to take the giant skull literally. So enjoy this system agnostic dungeon that is gross and fun. Enjoy!



The rotting corpse of Gol’togeroth the Ancient Giant lay among the Tugoren mountains. There the worshipers of Titonous struck him down in a fierce battle. The Worshipers strung up the bones of Gol’togeroth’s followers as a warning.

But such displays of brutality attract those who seek fortune, for why else such a warning exist? Legend has it that deep within the cave– in the rotting bowels of Gol’togeroth himself– treasures abound.

Gol’togeroth’s flesh is now as hard as the mountains that surround him. Thus, there is but one known way inside.


The Mouth of the Cave

Gol’thogeroth’s mouth hangs open and is the entrance to the dungeon. Scavengers have picked the skull clean.


Perception thresholds:


  • Low: Gol’thogeroth’s teeth are gone. Groups of songbirds nest in the eye sockets, both of which are picked completely clean.
  • Mid: In addition, they notice a small creature could squeeze through the collapsed nasal cavity to access the second part of the cave.
  • High: In addition, the cavities in the skull where the teeth were are dark but not completely empty. A group of marrow worms lies in wait to unravel, snatch unsuspecting prey, and pull them up into their hole to devour.


Marrow Worms

Marrow worms are ambush predators. As the name implies, they enjoy bones, not meat. They will eat around the flesh to devour the skeleton of their prey, leaving the meat for scavengers. They do not eat the scavengers, for they clean up the area beneath their traps, allowing more creatures to walk by without knowledge of the danger. The worms have eaten Gol’togeroth’s teeth.

As worms, they have no limbs. They use a combination of constriction and a sticky residue to cling to walls and ceilings.

Marrow worms deal the most damage on their first attack, assuming it is a surprise. They aim for vital areas, most commonly the head. They’ll try to bite it clean off if their prey is small enough. If not, they will wrap around their prey, pull it up into their cavity, and gnaw on it until it dies.


Getting past the marrow worms

If marrow worms see bones placed under their traps and do not perceive any threats, they will drop down and eat the bones provided. If properly occupied with eating, they will not attack.

Marrow worms do not have eyes and have poor hearing and smell. They rely on sensing vibrations. If anything were to disrupt this sense, they would not be able to sense the prey going beneath their traps.


The Throat

The floor of the cave turns soft, squishy, and rancid. While the mouth has decomposed, the rest of the innards are less exposed and still rotting. The stench is horrid, forcing all who have a sense of smell refrain from vomiting, or worse.


  • Low: The smell overtakes you. Your eyes water as vomit spews from your mouth. The taste is somehow better than the smell of the cave. The retching in your stomach does not cease. You suffer minor vision penalties from watery eyes and mild penalties to anything that requires you to breathe heavily (running, extended combat, climbing, etc.)
  • Mid: The smell starts to overtake you, but you push your discomfort into your belly. You suffer minor penalties to anything that requires you to breathe heavily (running, extended combat, climbing, etc.)
  • High: You can feel the stench in the air attaching to your skin and clothing. You know it won’t wash off for days. Better get used to it now.


As you continue, darkness overtakes the cave. Anyone who cannot see in the dark requires a light source or shall take the appropriate penalties. The fleshy throat is mid-transition from its once glossy red to a putrid black. Small burrows show the signs of scavengers eating away at the flesh, but there is too much meat to consume.

The throat is narrow. An average person can walk comfortably. A tall person must hunch forward and if their shoulders are wide enough, turn partially to the side. Small folk could stand next to each other and not touch the walls.


Event: Throat collapse

The pockets dug into the rotting flesh have compromised the structure of the throat. Worse, mists of stomach acid line the throat, eroding the flesh and smelling terrible. A horrid tearing sound echoes through the throat, and the ceiling begins to tear off as a large chunk falls. All creatures in the throat must attempt to avoid being smothered by the strip of falling, rotting flesh.


  • Low: The flesh falls, knocking the wind out of you and burying you beneath it. You immediately start to suffocate. You can offer little aid to get free or to help someone else free you.
  • Mid: The flesh falls on top of you. While smothered by its weight, it does not crush you. You can offer aid if someone else attempts to get you out, or you can attempt to cut your way out if you have a short blade.
  • High: The flesh falls, narrowly missing you. Viscera splashes upon you as it hits.


Cutting through any non-collapsed flesh is time-consuming and could create another collapse.


The Stomach

The mists of stomach acid thicken as the characters get closer to the stomach. Exposed items begin to sizzle. Exposed material on the characters will erode if they continue. Covering items or unequipped armor with a cloth of tucking it under their clothing will protect it. However, any item they use is considered exposed. Exposed items (armor, weapons, potions, books, etc.) risk breaking or degrading. Roll for each item, or if there are too many, roll at minimum of twice for each character’s items (dividing them as the DM sees fit).

  • 1-5: The item breaks
  • 6-10: The item has 2d4 uses left before breaking
  • 11-20: The item breaks on a critical failure (or another appropriate roll)
  • 21-30: The item is compromised, -3 (or appropriate) to all actions using the item until it is repaired
  • 31-40: The item is compromised, -2 (or appropriate) to all actions using the item until it is repaired
  • 41-50: The item is compromised, -1 (or appropriate) to all actions using the item until it is repaired
  • 51-70: The item holds the horrid stench of the rotting stomach acid. Anyone within 15 feet can easily smell it (a thorough cleaning can remove this)
  • 71-90: The item has a permanent tarnish that cannot be removed or fixed (cosmetic only)
  • 91-100: The item takes on the properties of acid, dealing extra acid damage, protecting against acid, or some other bonus related to acid

Venturing further, they find the stomach; a putrid pit of acid before them. While the acid is solid black, it is only ankle deep (if they can measure it). However, if a character touches the stomach acid, they take acid damage. If any item touches it, roll twice on the above chart and take the lower result.

The stomach is still intact, creating a 30 ft. x 30 ft. x 30 ft. room with the acid pools resting between the entrance and the exit. The stomach’s walls are smooth, making it difficult to climb, and poking any holes in it will allow the gas to escape and make the stomach collapse and flatten. Characters must cross the acid pit without puncturing the stomach lining or suffer the consequences of it collapsing, sending the acidic gas into the whole body.



Past the acid pit in the stomach, they must face the narrow corridor that is the winding maze of the intestines. Even humans struggle to move down the squishy, fleshy hall. Red bulbs growing from the ends of worms hang from the top and sides of the intestines. The strange worms move when touched but do not attack (though they are alive). What was once a simple switch-backing hall has many sections that have collapsed. Holes from scavengers eating portions of the intestines and stab wounds from giant swords connect layers of the intestines to create a maze.

Creatures as big as or larger than average humans suffer a small penalty when trying to run through or perform actions that require movements (such as fighting) within the intestines.


Osedax Roseus

The osedax roseus in this giant’s intestines are worm-like creatures that hang from the ceiling and walls. They are 3-6 inches long and only a few inches around. Their red plumbs on the end hang down to catch whatever passes below them to start eating it. However, they will not attempt to eat anything that doesn’t stay put for more than 5 minutes. They were a natural part of the giant’s digestion, but now that it’s dead, their scavenging its body for sustenance.

While the small osedax are the workers and have no defenses, they are not defenseless. 8-12 warrior osedax roam the intestines, attacking intruders and feeding the parts of their prey they do not eat to the smaller osedax. While they look just like the smaller osedax, they are around 6 feet long and will grapple and shred their prey, bones and all with their teeth inside their plumbs.

The warrior osedax will notice the scent of the intruders and pursue them. The scavengers get to make a stealth roll VS the character’s notice rolls to determine if the players can sense them coming. The osedax narrow frames allows them to move through the intestines with ease.

Piercing the intestine to make it to the next section is possible, but passing through is considered difficult (system dependent). The osedax can pierce through the intestines as part of their movement.



Once the players find what they are looking for, or if they must escape early, they can escape through the wounds the start in the intestines and lead through the giant’s flesh and out into the mountains. If you want one last challenge, have the warrior osedax chase them out of the wound, and make running through the torn flesh a challenge they must overcome or be caught by the pursuing osedax.




A giant of this size could easily devour people whole. Undigested treasures such as the unique equipment of wealthy adventurers and fallen Worshipers of Titonous are scattered throughout the intestines. Valuables contained within pouches made of acid-resistant material (such as a sheep stomach) are also scattered throughout, a few resting in the bottom of the acid pool of the stomach.

I’m intractable on

  • Reddit (Praising others, Dark Souls theories, and posting my own goodies)
  • Twitter (Bite-sized RPG shenanigans)
  • Instagram (Mostly pictures of costumes)

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