Dungeon Terrain


Rooms in dungeons vary in shape and size. Although many are simple in construction and appearance, particularly interesting rooms have multiple levels joined by stairs, ramps, or ladders, as well as statuary, altars, pits, chasms, bridges, and more.

Underground chambers are prone to collapse, so many rooms— particularly large ones—have arched ceilings or pillars to support the weight of the rock overhead.

Common dungeon rooms fall into the following broad categories.

Guard Post: Intelligent, social denizens of the dungeon will generally have a series of adjacent rooms they consider “theirs,” and they’ll guard the entrances to that common area.

Living Quarters: All but the most nomadic creatures have a lair where they can rest, eat, and store their treasure. Living quarters commonly include beds (if the creature sleeps), possessions (both valuable and mundane), and some sort of food preparation area. Noncombatant creatures such as juveniles and the elderly are often found here.

Work Area: Most intelligent creatures do more than just guard, eat, and sleep, and many devote rooms to magic laboratories, workshops for weapons and armor, or studios for more esoteric tasks.

Shrine: Any creature that is particularly religious may have some place dedicated to worship, and others may venerate something of great historical or personal value. Depending on the creature’s resources and piety, a shrine can be humble or extensive. A shrine is where PCs will likely encounter NPC clerics, and it’s common for wounded monsters to flee to a shrine friendly to them when they seek healing.

Vault: Well protected, often by a locked iron door, a vault is a special room that contains treasure. There’s usually only one entrance - an appropriate place for a trap.

Crypt: Although sometimes constructed like a vault, a crypt can also be a series of individual rooms, each with its own sarcophagus, or a long hall with recesses on either side—shelves to hold coffins or bodies.

Those who are worried about undead rising from the grave take the precaution of locking and trapping a crypt from the outside - making the crypt easy to get into but difficult to leave. Those worried about tomb robbers make their crypts difficult to get into. Some builders do both, just to be on the safe side.


All dungeons have rooms, and most have corridors. While most corridors simply connect rooms, sometimes they can be encounter areas in their own right because of traps, guard patrols, and wandering monsters out on the hunt.

Corridor Traps: Because passageways in dungeons tend to be narrow, offering few movement options, dungeon builders like to place traps in them. In a cramped passageway, there’s no way for intruders to move around concealed pits, falling stones, arrow traps, tilting floors, and sliding or rolling rocks that fill the entire passage. For the same reason, magic traps such as glyphs of warding are effective in hallways as well.

Mazes: Usually, passages connect chambers in the simplest and straightest manner possible. Some dungeon builders, however, design a maze or a labyrinth within the dungeon. This sort of construction is difficult to navigate (or at least to navigate quickly) and, when filled with monsters or traps, can be an effective barrier.

A maze can be used to cut off one area of the dungeon, deflecting intruders away from a protected spot. Generally, though, the far side of a maze holds an important crypt or vault — someplace that the dungeon’s regular inhabitants rarely need to get to.

Miscellaneous Features

Stairs: The usual way to connect different levels of a dungeon is with stairs. Straight stairways, spiral staircases, or stairwells with multiple landings between flights are all common in dungeons, as are ramps (sometimes with an incline so slight that it can be difficult to notice; Perception DC 15). Stairs are important accessways, and are sometimes guarded or trapped. Traps on stairs often cause intruders to slide or fall down to the bottom, where a pit, spikes, a pool of acid, or some other danger awaits.

Gradual Stairs: Stairs that rise less than 5 feet for every 5 feet of horizontal distance they cover don’t affect movement, but characters who attack a foe below them gain a +1 bonus on attack rolls from being on higher ground. Most stairs in dungeons are gradual, except for spiral stairs (see below).

Steep Stairs: Characters moving up or down steep stairs (which rise at a 45- degree angle or steeper) can move at only half normal speed. Characters running or charging down steep stairs must succeed on a DC 10 Acrobatics check. Those who fail stumble and must end their movement 1d2×5 feet later. Characters who fail by 5 or more fall down the stairs, taking 1d4 points of damage per 10 feet they fall; additionally, they end up prone at the bottom. Steep stairs increase the DC of Acrobatics checks by 5.

Spiral Stairs: This form of steep stairs is designed to make defending a fortress easier. Characters gain 1/2 cover (+2 bonus to AC, +1 to Reflex saves) against foes below them on spiral stairs because they can easily duck around the staircase’s central support.

Railings and Low Walls: Stairs that are open to large rooms often have railings or low walls. They function as described for ledges (see Special Floors).

Bridge: A bridge connects two higher areas separated by a lower area, stretching across a chasm, over a river, or above a pit. A simple bridge might be a single wooden plank, while an elaborate one could be made of mortared stone with iron supports and side rails.

Narrow Bridge: If a bridge is particularly narrow, such as a series of planks laid over lava fissures, treat it as a ledge (see Special Floors). It requires an Acrobatics check (DC dependent on width) to cross such a bridge.

Rope Bridge: Constructed of wooden planks suspended from ropes, a rope bridge is convenient because it’s portable and can be easily removed. It takes two full-round actions to untie one end of a rope bridge, but a DC 10 Dex check reduces the time to a move action. If only one of the two supporting ropes is attached, everyone on the bridge must succeed on a DC 15 Reflex save to avoid falling off, and thereafter must make DC 15 Climb checks to move along the remnants of the bridge. Rope bridges are usually 5 feet wide. The two ropes that support them have 8 hit points each.

Drawbridge: Some bridges have mechanisms that allow them to be extended or retracted from the gap they cross. Typically, the winch mechanism exists on only one side of the bridge. It takes a move action to lower a drawbridge, but the bridge doesn’t come down until the beginning of the lowering character’s next turn. It takes a full-round action to raise a drawbridge; the drawbridge is up at the end of the action. Particularly long or wide drawbridges may take more time to raise and lower, and some may require Strength checks to rotate the winch.

Railings and Low Walls: Some bridges have railings or low walls along the sides. If a bridge does, the railing or low walls affect Balance checks and bull rush attempts as described for ledges (see Special Floors). Low walls likewise provide cover to bridge occupants (the degree depends on the height of the wall and the creature).

Chutes and Chimneys: Stairs aren’t the only way to move up and down in a dungeon. Sometimes a vertical shaft connects levels of a dungeon or links a dungeon with the surface. Chutes are usually traps that dump characters into a lower area — often a place featuring some dangerous situation with which they must contend.

Pillar: A common sight in any dungeon, pillars and columns give support to ceilings. The larger the room, the more likely it has pillars. As a rule of thumb, the deeper in the dungeon a room is, the thicker the pillars need to be to support the overhead weight. Pillars tend to be polished and often have carvings, paintings, or inscriptions upon them.

Slender Pillar: These pillars are only a foot or two across, so they don’t occupy a whole square. A creature standing in the same square as a slender pillar gains 1/2 cover (+2 bonus to Armor Class and a +1 bonus to Reflex saves). The presence of a slender pillar does not otherwise affect a creature’s fighting space, because it’s assumed that the creature is using the pillar to its advantage when it can. A typical slender pillar has AC 4, hardness 8, and 250 hit points.

Wide Pillar: These pillars take up an entire square and provide 9/10 cover to any creature of Medium or smaller size behind them. They have AC 3, hardness 8, and 900 hit points. A DC 20 Climb check is sufficient to climb most pillars; the DC increases to 25 for polished or unusually slick ones.

Stalagmite/Stalactite: These tapering natural rock columns extend from the floor (stalagmite) or the ceiling (stalactite). Stalagmites and stalactites function as slender pillars.

Statue: Most statues function as wide pillars, taking up a square and providing cover. Some statues are smaller and act as slender pillars. A DC 15 Climb check allows a character to climb a statue.

Tapestry: Elaborately embroidered patterns or scenes on cloth, tapestries hang from the walls of well-appointed dungeon rooms or corridors. Crafty builders take advantage of tapestries to place alcoves, concealed doors, or secret switches behind them.

Tapestries provide total concealment (+4 deflection bonus to AC) to characters behind them if they’re hanging from the ceiling, or concealment (+2 bonus to AC) if they’re flush with the wall. Climbing a big tapestry isn’t particularly difficult, requiring a DC 15 Climb check (or DC 10 if a wall is within reach).

Pedestal: Anything important on display in a dungeon, from a fabulous treasure to a coffin, tends to rest atop a pedestal or a dais. Raising the object off the floor focuses attention on it (and, in practical terms, keeps it safe from any water or other substance that might seep onto the floor). A pedestal is often trapped to protect whatever sits atop it. It can conceal a secret trapdoor beneath itself or provide a way to reach a door in the ceiling above itself.

Only the largest pedestals take up an entire square; most provide no cover.

Pool: Pools of water collect naturally in low spots in dungeons (a dry dungeon is rare). Pools can also be wells or natural underground springs, or they can be intentionally created basins, cisterns, and fountains. In any event, water is fairly common in dungeons, harboring sightless fish and sometimes aquatic monsters. Pools provide water for dungeon denizens, and thus are as important an area for a predator to control as a watering hole aboveground in the wild.

Shallow Pool: If a square contains a shallow pool, it has roughly 1 foot of standing water. It costs 2 squares of movement to move into a square with a shallow pool (and movement in the pool is halved), and the DC of Acrobatics checks in such squares increases by 2.

Deep Pool: These squares have at least 4 feet of standing water. It costs Medium or larger creatures 4 squares of movement to move into a square with a deep pool (and movement is reduced to 1/4), or characters can swim if they wish. Small or smaller creatures must swim to move through a square containing a deep pool. Tumbling is impossible in a deep pool. The water in a deep pool provides 1/2 cover for Medium or larger creatures. Smaller creatures gain 9/10ths cover (+8 bonus to AC, +4 bonus on Reflex saves). Medium or larger creatures can crouch as a move action to gain this improved cover. Creatures with 9/10ths cover take a -10 penalty on attacks against creatures that aren’t also underwater.

Deep pool squares are usually clustered together and surrounded by a ring of shallow pool squares. Both shallow pools and deep pools impose a –2 circumstance penalty on Stealth checks.

Special Pools: Through accident or design, a pool can become magically enhanced. Rarely, a pool or a fountain may be found that has the ability to bestow beneficial magic on those who drink from it. However, magic pools are just as likely to curse the drinker. Typically, water from a magic pool loses its potency if removed from the pool for more than an hour or so.

Some pools have fountains. Occasionally these are merely decorative, but they often serve as the focus of a trap or the source of a pool’s magic.

Most pools are made of water, but anything’s possible in a dungeon. Pools can hold unsavory substances such as blood, poison, oil, or magma. And even if a pool holds water, it can be holy water, saltwater, or water tainted with disease.

Elevator: In place of or in addition to stairs, an elevator (essentially an oversized dumbwaiter) can take inhabitants from one dungeon level to the next. Such an elevator may be mechanical (using gears, pulleys, and winches) or magical (such as a levitate spell cast on a movable flat surface). A mechanical elevator might be as small as a platform that holds one character at a time, or as large as an entire room that raises and lowers. A clever builder might design an elevator room that moves up or down without the occupants’ knowledge to catch them in a trap, or one that appears to have moved when it actually remained still.

A typical elevator ascends or descends 10 feet per round at the beginning of the operator’s turn (or on initiative count 0 if it functions without regard to whether creatures are on it). Elevators can be enclosed, can have railings or low walls, or may simply be treacherous floating platforms.

Ladders: Whether free-standing or rungs set into a wall, a ladder requires a DC 0 Climb check to ascend or descend.

Shifting Stone or Wall: These features can cut off access to a passage or room, trapping adventurers in a dead end or preventing escape out of the dungeon. Shifting walls can force explorers to go down a dangerous path or prevent them from entering a special area. Not all shifting walls need be traps. For example, stones controlled by pressure plates, counterweights, or a secret lever can shift out of a wall to become a staircase leading to a hidden upper room or secret ledge.

Shifting stones and walls are generally constructed as traps with triggers and Search and Disable Device DCs. However they don’t have Challenge Ratings because they’re inconveniences, not deadly in and of themselves.

Teleporters: Sometimes useful, sometimes devious, places in a dungeon rigged with a teleportation effect (such as a teleportation circle) transport characters to some other location in the dungeon or someplace far away. They can be traps, teleporting the unwary into dangerous situations, or they can be an easy mode of transport for those who built or live in the dungeon, good for bypassing barriers and traps or simply to get around more quickly. Devious dungeon designers might place a teleporter in a room that transports characters to another seemingly identical room so that they don’t even know they’ve been teleported. A detect magic spell will provide a clue to the presence of a teleporter, but direct experimentation or other research is the only way to discover where the teleporter leads.

Altars: Temples—particularly to dark gods—often exist underground. Usually taking the form of a stone block, an altar is the main fixture and central focus of such a temple. Sometimes all the other trappings of the temple are long gone, lost to theft, age, and decay, but the altar survives. Some altars have traps or powerful magic within them. Most take up one or two squares on the grid and provide cover to creatures behind them.

Obstacles and Hazards

Obstacle/Hazard Effect
Acid tank 1d6 damage per round, or 10d6 per round for total immersion; plus poison fumes.
Antimagic field Negates all spells or magical effects.
Dimensional anchor trap Blocks bodily extradimensional travel.
Hurricane-force winds Ranged attacks impossible, flight virtually impossible.
Lava pit 2d6 damage per round, or instant death for total immersion; plus continuing damage.
Permanent prismatic sphere Requires seven different spells to bypass.
Permanent solid fog Move at one-tenth normal speed, –2 penalty on attack and damage (good when coupled with incorporeal monsters).
Permanent wall of force Blocks most spells and ethereal travel, can’t be dispelled.
Three-dimensional dungeons Levitation/flying required to move between areas.
Unconnected rooms Teleportation required to move between areas.
Variable gravity As reverse gravity, but direction random each round.

Cave-Ins And Collapses (CR 8): Cave-ins and collapsing tunnels are extremely dangerous. Not only do dungeon explorers face the danger of being crushed by tons of falling rock, even if they survive they may be buried beneath a pile of rubble or cut off from the only known exit. A cave-in buries anyone in the middle of the collapsing area, and then sliding debris damages anyone in the periphery of the collapse. A typical corridor subject to a cave-in might have a bury zone with a 15-foot radius and a 10-foot-radius slide zone extending beyond the bury zone. A weakened ceiling can be spotted with a DC 20 Knowledge (architecture and engineering) or DC 20 Craft (stonemasonry) check. Remember that Craft checks can be made untrained as Intelligence checks. A dwarf can make such a check if he simply passes within 10 feet of a weakened ceiling.

A weakened ceiling may collapse when subjected to a major impact or concussion. A character can cause a cave-in by destroying half the pillars holding the ceiling up.

Characters in the bury zone of a cave-in take 8d6 points of damage, or half that amount if they make a DC 20 Reflex save. They are subsequently buried. Characters in the slide zone take 3d6 points of damage, or no damage at all if they make a DC 15 Reflex save. Characters in the slide zone who fail their saves are partially buried (they are pinned, but don't suffer the chance of suffocation).

Characters take 1d6 points of nonlethal damage per minute while buried; additionally, they must make a DC 15 Constitution check (+1 per hour) or fall unconscious. If the character falls unconscious, he takes 1d6 points of lethal damage each minute thereafter until freed or dead.

Characters who aren’t buried can dig out their friends. In 1 minute, using only her hands, a character can clear rocks and debris equal to five times her heavy load limit. The amount of loose stone that fills a 5-foot-by-5-foot area weighs one ton (2,000 pounds). Armed with an appropriate tool, such as a pick, crowbar, or shovel, a digger can clear loose stone twice as quickly as by hand. A character who is pinned can be dug out in 5 man-rounds (that is, one character digging for 5 rounds, five digging for 1 round, etc.).

Slimes, Molds, and Fungi

In a dungeon’s damp, dark recesses, molds and fungi thrive. While some plants and fungi are monsters and other slime, mold, and fungus is just normal, innocuous stuff, a few varieties are dangerous dungeon encounters. For purposes of spells and other special effects, all slimes, molds, and fungi are treated as plants. Like traps, dangerous slimes and molds have CRs, and characters earn XP for encountering them.

A form of glistening organic sludge coats almost anything that remains in the damp and dark for too long. This kind of slime, though it might be repulsive, is not dangerous.

Molds and fungi flourish in dark, cool, damp places. While some are as inoffensive as the normal dungeon slime, others are quite dangerous. Mushrooms, puffballs, yeasts, mildew, and other sorts of bulbous, fibrous, or flat patches of fungi can be found throughout most dungeons. They are usually inoffensive, and some are even edible (though most are unappealing or odd-tasting).

Green Slime (CR 4): This dungeon peril is a dangerous variety of normal slime. Green slime devours flesh and organic materials on contact and is even capable of dissolving metal. Bright green, wet, and sticky, it clings to walls, floors, and ceilings in patches, reproducing as it consumes organic matter. It drops from walls and ceilings when it detects movement (and possible food) below.

A single 5-foot square of green slime deals 1d6 points of Constitution damage per round while it devours flesh. On the first round of contact, the slime can be scraped off a creature (most likely destroying the scraping device), but after that it must be frozen, burned, or cut away (dealing damage to the victim as well). Anything that deals cold or fire damage, sunlight, or a remove disease spell destroys a patch of green slime. Against wood or metal, green slime deals 2d6 points of damage per round, ignoring metal’s hardness but not that of wood. It does not harm stone.

Phosphorescent Fungus (No CR): This strange underground fungus grows in clumps that look almost like stunted shrubbery. Drow elves cultivate it for food and light. It gives off a soft violet glow that illuminates underground caverns and passages as well as a candle does. Rare patches of fungus illuminate as well as a torch does.

Brown Mold (CR 2): Brown mold feeds on warmth, drawing heat from anything around it. It normally comes in patches 5 feet in diameter, and the temperature is always cold in a 30-foot radius around it. Living creatures within 5 feet of it take 3d6 points of nonlethal cold damage. Fire brought within 5 feet of brown mold causes it to instantly double in size. Cold damage, such as from a cone of cold, instantly destroys it.

Yellow Mold (CR 6): If disturbed, a 5-foot square of this mold bursts forth with a cloud of poisonous spores. All within 10 feet of the mold must make a DC 15 Fortitude save or take 1d6 points of Constitution damage. Another DC 15 Fortitude save is required 1 minute later—even by those who succeeded on the first save—to avoid taking 2d6 points of Constitution damage. Fire destroys yellow mold, and sunlight renders it dormant.

Flux Slime (CR 21): Flux slime appears as a clear, viscous liquid that seeps from some unseen origin point. This origin point is extradimensional, so the slime may even appear in midair. As the slime flows, it settles and fills the area around the origin point.

Flux slime seems to be an inert substance, devoid of sentience. It is not caustic or toxic, but it radiates an antimagic field (caster level 21) within a radius of 10 feet. Any quantity of slime that is removed from the main mass yellows and hardens in a matter of minutes, turning into a flaky material that will not adhere to anything.

In reality, flux slime is a growth with a ravenous appetite for magical forces. It is a natural draining phenomenon: Magical energy drains through the origin point in one direction in exchange for the residue on the far side. The antimagic field a flux slime generates is actually the byproduct of the consumption of magical energy.

In addition to the field’s effects, magic items that come into contact with flux slime permanently lose their magical abilities, and creatures with spell-like or supernatural abilities that come into contact with it take 2d6 points of Constitution damage per round while it devours flesh. Creatures without such abilities are immune to this effect.

On the first round of contact, the slime can be scraped off a creature, but after that it must be frozen, burned, or cut away (dealing damage to the victim as well). Extreme cold, heat, or sunlight destroys a patch of flux slime.

When destroyed, a patch of slime releases the byproducts of its magical digestion in a dangerous burst that radiates out 50 feet. All creatures caught in this burst are subject to some random and permanent transmutation effect, as generated on the table below; they can make a DC 29 Fort save to resist it.

d% Result
01–10 Blindness (as blindness/deafness spell)
11–16 Cursed (as bestow curse spell; –4 enhancement penalty on attack rolls, saving throws, ability checks, and skill checks)
17–26 Deafness (as blindness/deafness spell)
27–32 Disintegrate (subject is destroyed by a disintegrate spell)
33–40 Etherealness (as etherealness spell)
41–48 Gaseous (as gaseous form spell)
49–54 Iron body (as iron body spell)
55–60 Petrification (as flesh to stone spell)
61–68 Plane shift (subject instantly transports to a random plane)
69–74 Polymorph (as polymorph other spell; choose form randomly)
75–80 Reverse gravity (flux slime becomes the center of a reverse gravity spell).
81–88 Slowed (as the slow spell)
89–94 Temporal stasis (as temporal stasis spell)
95–00 Reverse aging (subject gets younger each year, disappearing at moment of "birth")

After the burst, the extradimensional origin point is sealed.


Adventurers crawl around in sewers, old tombs, and similar places, or disturb rotten corpses or undead best left alone. As with slimes and molds, they often come into contact with parasitic organisms.

Ear Seekers (CR 1)

Ear seekers are small maggot-like insects that occupy decaying wood. As adults, they are harmless as they spend their days deep within rotting logs happily eating the wood. As larvae, the ear seekers can be lethal to warm-blooded creatures.

Female ear seekers lay their eggs in warm, moist areas. Generally, the warm moistness of decaying vegetable matter suits them. On rare occasions, however, they will enter the ear of a living creature and deposit their eggs there. Adventurers are often the victims in this case – those who place their ears up against an old door to listen for enemies, or who batter down old, rotten doors or break old furnishings in which the ear seekers reside.

An adult ear seeker will lay 1d8+8 tiny eggs and then fly off to die. The incubation time of the eggs is 4d6 hours, at which time the tiny larvae hatch and begin to consume the only available food source: the surrounding flesh. Preferring warmth, they will burrow inwards in the direction of the most food and body heat. The host must make a Fort save (DC 18) or die in 1d4 days as the ear seekers devour its brain tissue. Even if the save is successful, he suffers 3d6 points of Int and Wis drain, which can't be recovered except by a regenerate, limited wish, or similar spell.

During this time, the host suffers intense headaches and may hear strange scuttling noises (the ear seekers moving around near the ear canal). He may exhibit any or all of the following, depending on which part of the brain the larvae are consuming: confusion, odd, jerky movements, impaired speech, seizures, inability to concentrate or cast spells, headaches, and nausea.

After sating themselves, the larvae will turn to pupae. This stage lasts about two weeks, at which time adult ear seekers crawl out of the host and fly away.

Rot Grubs (CR 2)

Rot grubs are small maggot-like parasites that live in garbage and rotting corpses. They are spread by living hosts coming into contact with them - usually rats, but sometimes adventurers as well.

Upon contact with the skin of a living host, rot grubs attempt to burrow into the flesh. Immediate (in the same round) application of fire will destroy them; otherwise they get under the skin and are much harder to dislodge. Once inside the body, they burrow through the victim's flesh toward the heart, taking 1d4 minutes to do so, whereupon they begin to breed and spread their progeny through the bloodstream.

This process takes 1d4+1 hours; the victim takes 1d4 points of Con damage per hour. If he dies during this time, the transformation to a graveworm zombie is not fully complete and the victim does not rise, but the corpse remains a breeding ground for the worms, which seek to infect any living beings that come into contact with it. If the victim survives the entire process, he must make a Fort save (DC 30) each hour thereafter or die immediately as the worms collectively attack the major organs – heart, liver, kidneys, brain, etc. The only cure at this point is a parasite purge or a heal spell.

Graveworms (CR 3)

Graveworms are magically modified rot grubs, believed to have been developed by necromancers (probably undead). They are usually only found on graveworm zombies, but can infest living hosts and turn them to graveworm zombies also.

They are identical to rot grubs except for the following:

The immediate application of fire, holy water, or a holy item will destroy a burrowing graveworm; otherwise, the parasite purge must be followed with remove curse (a heal spell by itself will also work). If parasite purge is used without the remove curse, there is a chance (10%) some residue of the graveworms could reinfect the victim and start the process all over again in 1d4 months.

Unless the body has been cleansed (casting parasite purge and remove curse or bless on it), any attempts to raise someone who has died from a graveworm infestation but not risen as a zombie will automatically fail. If the body is not cleansed or burned, it has a 50% chance of rising as a graveworm zombie in 24 hours.

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