Return to Undermountain
Room 7: Ghoul Pool (EL 7)
By Matthew Sernett

Room Summary

Creatures: (6) Six ghouls.
Traps: (3) A portcullis, a moving wall, and a camouflaged pit.
Terrain: Normal, but the pit has deep water requiring Swim checks.
Lighting Conditions: Darkness.
Magic: None except treasure (moderate divination [scarab, golembane] and faint transmutation [+1 silvered longsword]). Note that the magic cannot be detected until the pit trap cover falls open due to a thin sheet of lead on the bottom of the pit cover.
Detectable Alignments: None or faint evil. The ghouls' alignment cannot be detected until the pit trap cover falls open due to a thin sheet of lead on the bottom of the pit cover. Similarly, detect undead cannot reveal them until the trapdoor is open.
Secrets: (2)The door across the room is false. Also, the dark water in the pit hides the treasure.
Treasure: (4,905 gp) A golembane scarab worth 2500 gp, and a +1 silvered longsword worth 2,405 gp.

Relevant Skill Checks

Disable Device DC 20: This result can disable the portcullis trap once it is discovered.

Disable Device DC 29: This result can disable the moving wall or camouflaged pit trap once either is discovered.

Escape Artist DC 30: A PC who succeeds to this degree on an Escape Artist check can squeeze through the bars of the portcullis trap. See the squeezing rules on page 148 of the Player's Handbook. A Tiny or smaller creature can automatically squeeze through the trap's bars. A Large or larger creature cannot move through the bars.

Jump DC (Varies): PCs can make jump checks to clear the pit. PCs who delay jumping for too long might be required to make a standing Jump check. See the Player's Handbook for Jump rules.

If the portcullis is down, a PC must attempt to grab it, the lip of the hallway floor, or the top edge of the fallen trap door to avoid falling into the pit at the end of a successful jump (an unsuccessful jump lands a PC in the pit). Grabbing requires a DC 15 Reflex save. If a PC in the hall attempts to grab the jumper, the jumping PC gains a +2 bonus on the Reflex save. Failure results in the PC plunging into the pit.

Search DC 24: PCs must have the trapfinding ability to make this check. A PC with the trapfinding ability who searches the ceiling area near the entrance to the room finds the portcullis trap.

Search DC 24: Non-dwarf PCs must have the trapfinding ability to make this check. A PC with the trapfinding ability who searches the floor near the entrance to the room finds the pit trap. One who searches near the far wall discovers the moving wall trap. One who searches the false door discovers it is false.

A dwarf can make this check automatically when he comes within 10 feet of the false door, pit trap, or moving wall trap. You should secretly roll for any dwarf PCs. A success about either trap reveals to the dwarf that it (the floor or wall) seems unstable and that it doesn't seem attached to the surrounding room.

Spot DC 15: A PC who takes a standard action to peer into the dark water can make a Spot check to see what's in it. A success to this degree allows a PC to spy a ghoul's flailing arm or rotted face just before it becomes hidden by the water again. This brief glimpse is enough to allow a PC to know what square the ghoul occupies.

Open Locks DC 25: A success to this degree can open the average quality lock in the false door.

Strength DC 10: This Result allows a PC to aid another (granting a +2 bonus) in the following Strength checks.

Strength DC 24: This check result allows a PC to bend one of the iron bars in the portcullis. This gives PCs trying to move through the bars a +5 bonus on their Escape Artist checks.

Strength DC 30: A Strength check this high allows a PC to break one of the iron bars free from its moorings. This allows any PC up to Medium size to squeeze through the bars without the need of an Escape Artist check. See the squeezing rules on page 148 of the Player's Handbook.

Alternatively, a PC who makes a Strength check to lift the portcullis and gets this result can actually lift the portcullis into the ceiling, but the portcullis remains up only if the PC continues to make the check on the following rounds or the trap is reset. A PC who loses his grip on the raised bars or intentionally lets go without them being secured is attacked by the trap as the portcullis comes down again. Note that if a bar is bent by the PCs, the portcullis can't be lifted until the bar is bent straight again.

Strength DC 20: A Strength check made with this result while pulling on the ring attached to the false door rips the ring from its moorings. If a PC is using it to hang above the pit at the time, the PC falls into the pit.

Swim DC 15: A PC must succeed at a DC 15 Swim check to move in the rough water of the pit. See the Swim rules in the Player's Handbook for details.

The Map

The map for this room is available in two different sizes: One serves as a reference for the DM, and the other is a map with a grid that works nicely with your miniatures.

Each map is presented as a compressed (zipped) Adobe Portable Document Format file (pdf). You need to have Adobe Reader installed to use it. Adobe Reader can be downloaded for free from the Adobe website.

Room Location on the Poster Map: This room is on piece 5 of the poster map. You can see the pieces in thumbnail size in the introduction to this series. For a better idea of where this room is, please view the Article Reference Map.

For this encounter to be most effective, you should describe the room as you would any other normal empty room in the dungeon. Here is an example:

This small barren room has a door in the south wall opposite your entrance.

This room is one grand trap. The door in south wall is false. It appears in all respects to be a normal stone door, but the door is built into the wall and no passage exists beyond it. It appears locked with an average quality lock. A PC can attempt to unlock the lock with the Open Locks skill or a knock spell, but this has no effect besides unlocking the lock. Pulling on the iron ring to open the door proves useless, but allow the PCs to make Strength checks.

Several traps activate once at least 20 pounds of pressure is put on the floor in front of the false door. When this happens, read the following text.

Suddenly a tremendous boom and crash simultaneously fill the room! The northern 10 feet of the floor swings downward and back toward the north wall, slamming against it like a door caught in the wind. At the same time, a portcullis crashes down blocking the exit from the room. An awful stench then hits your noise: an overpowering smell of rotted flesh and foul water. Looking into the pit that now yawns on the north side of the room, you see a 15-foot drop to some nearly opaque, almost black liquid. Something -- a creature, and perhaps more than one -- thrashes below the surface.

Then you hear a grinding noise behind you. You can see the south wall slowing moving toward the pit. It's going to push you in!

All the following traps have a manual reset lever hidden behind a secret panel in a nearby room of your choice (Search DC 20 reveals the panel). Simply flipping the lever causes the machinery to draw back the wall, draw up the portcullis, and lift the trap door in the floor.

Well-Hidden Portcullis Trap: CR 2; mechanical; location trigger; manual reset; Atk +10 melee (3d6 piercing); Search DC 20; Disable Device DC 29.

Damage applies only to those underneath the portcullis. Since the portcullis is placed on a vertice rather than in a square, it is likely that only a Large or larger creature can be struck by it. A creature struck by the portcullis is considered pinned beneath it until the portcullis is lifted.

Moving Wall Trap: CR 2; mechanical; location trigger; manual reset; wall moves; Search DC 24; Disable Device DC 29.

The wall moves 0 feet on round of activation and 5 feet per round after that (moving at the beginning of the round). It stops moving when it meets the north wall (thus sealing the pit shut). Behind the leading edge of the wall lies 10 feet of solid stone, so once the wall moves over the pit, it's unlikely anyone in the pit will escape unless someone finds the lever to reset the trap.

Camouflaged Pit Trap: CR 2; mechanical; location trigger; manual reset; DC 20 Reflex save allows a PC to grab the portcullis or top edge of the trap door if on the north side, or to grab the pit edge if on the south side; 30 feet deep with 15 feet of water (0 damage for fall); multiple targets (anyone in the squares of the trap); Search DC 24; Disable Device DC 29.

The bottom 15 feet of this pit is filled with diseased water. Anyone who falls in the water is exposed to blinding sickness and filth fever each round (see page 292 of the Dungeon Master's Guide for details). The water also contains the creatures in this room: ghouls.

In addition, the water in the pit has become infused with the ghouls' stench, and any creature in the water or within 10 feet of its surface must make a DC 15 Fortitude save or be sickened for 1d6+4 minutes. A creature that makes the save cannot be affected by the water's stench for 24 hours, but if a ghoul gets out of the water, its stench can affect the PCs normally.

Ghouls (6): Use the Ghoul miniature from Harbinger or the ghoul statistics presented in the Monster Manual.

Six ghouls float upright 5 feet below the surface of the water. They are chained by rusted leg irons to the floor of the pit. The ghouls gave up on breaking the chains long ago, and now they're mad with hunger. They attack any creature that falls in the water, using their natural attacks or grappling the PCs in the hopes of drowning them. If a ghoul grapples a PC, the PC is pulled into the ghoul's space due to the leg irons preventing the ghoul from moving upward. A PC can resist being pulled into the ghoul's space by making a Swim check that exceeds the ghoul's grapple check. The Swim check is in addition to the normal grapple check to establish a grapple.

The ghouls and any PCs in the water must follow the rules for underwater combat on page 92 and 93 in the Dungeon Master's Guide. Briefly, fighting underwater causes the ghouls to suffer a -2 penalty on attacks and grapple checks. Damage from a ghoul's natural attacks is halved, but damage from grapple attacks is not halved. The ghouls must make a DC 15 Swim check each round or be considered off-balance (no Dex bonus to AC, and foes get +2 to attack it). The ghouls have total cover from PCs not in the water (unless the PC is subject to a freedom of movement effect). The dark water gives concealment to the PCs and ghouls who face one another in it.

Treasure: Two items of note lie beneath the water and constitute the treasure: a golembane scarab and a +1 silvered longsword (now black with corrosion but still functional). Searching for the items by hand is nearly impossible (DC 35 Search check for each) but a detect magic spell and a few rounds of concentration readily reveals their location to the caster.

Adventure Hooks and Tie-Ins

  • You can increase the difficulty of this encounter by putting it in a smaller room, changing the type or increasing the number of undead, or by increasing the Search and Disable Device DCs associated with the traps.

  • You can decrease the difficulty of this encounter by doing the opposite of the suggestions above and by having the moving wall stop at the edge of the pit.

  • You could put a door or secret door in the pit under the water or just above the water line.

  • The golembane scarab might presage a later encounter with a golem.

































Need more information? Check the Return to Undermountain: An Introduction for more details.

Article Reference Map

About the Author

Once editor-in-chief of Dragon Magazine and now a game designer at Wizards of the Coast, Matthew Sernett wrote in a Dragon editorial that there's nothing in D&D he likes better than when the adventurers flee through the dungeon, running pell-mell through traps and past monsters because what chases them is worse. When he wrote that, Matthew was thinking about Undermountain.


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