Chapter 5: Adventure Environments

Dungeon Location

You can use the Dungeon Location table to determine the locale of your dungeon. You can roll on the table or choose an entry that inspires you.

Dungeon Location

Exotic Location

Dungeon Creator

A dungeon reflects its creators. A lost temple of the yuan-ti, choked by overgrown jungle plants, might feature ramps instead of stairs. Caverns carved by a beholder’s disintegration eye ray have walls that are unnaturally smooth, and the beholder’s lair might include vertical shafts connecting different levels. Amphibious monsters such as kuo-toa and aboleths use water to protect the innermost reaches of their lairs from air-breathing intruders.

Details bring a dungeon setting’s personality to life. Great bearded faces might be carved on the doors of a dwarven stronghold and might be defaced by the gnolls who live there now. Spiderweb decorations, torture chambers, and slave pens might be common features in a vault built by drow, telling something about that location and its occupants.

The Dungeon Creator table includes creatures that typically build dungeons. You can choose a creator from the table or roll randomly, or choose some other dungeon builder appropriate for your campaign.

Dungeon Creator

Cults and Religious Groups

NPC Alignment

NPC Class

Dungeon Purpose

Except in the case of a natural cavern, a dungeon is crafted and inhabited for a specific purpose that influences its design and features. You can choose a purpose from the Dungeon Purpose table, roll one at random, or use your own ideas.

Dungeon Purpose

Death Trap. This dungeon is built to eliminate any creature that dares to enter it. A death trap might guard the treasure of an insane wizard, or it might be designed to lure adventurers to their demise for some nefarious purpose, such as to feed souls to a lich’s phylactery.

Lair. A lair is a place where monsters live. Typical lairs include ruins and caves.

Maze. A maze is intended to deceive or confuse those who enter it. Some mazes are elaborate obstacles that protect treasure, while others are gauntlets for prisoners banished there to be hunted and devoured by the monsters within.

Mine. An abandoned mine can quickly become infested with monsters, while miners who delve too deep can break through into the Underdark.

Planar Gate. Dungeons built around planar portals are often transformed by the planar energy seeping out through those portals.

Stronghold. A stronghold dungeon provides a secure base of operations for villains and monsters. It is usually ruled by a powerful individual, such as a wizard, vampire, or dragon, and it is larger and more complex than a simple lair.

Temple or Shrine. This dungeon is consecrated to a deity or other planar entity. The entity’s worshipers control the dungeon and conduct their rites there.

Tomb. Tombs are magnets for treasure hunters, as well as monsters that hunger for the bones of the dead.

Treasure Vault. Built to protect powerful magic items and great material wealth, treasure vault dungeons are heavily guarded by monsters and traps.

History

In most cases, the original architects of a dungeon are long gone, and the question of what happened to them can help shape the dungeon’s current state.

The Dungeon History table notes key events that can transform a site from its original purpose into a dungeon for adventurers to explore. Particularly old dungeons can have a history that consists of multiple events, each of which transformed the site in some way.

Dungeon History

Dungeon Factions

A dungeon is sometimes dominated by a single group of intelligent humanoids, whether a tribe of orcs that have taken over a cavern complex or a gang of trolls inhabiting an aboveground ruin. Other times, particularly in larger dungeons, multiple groups of creatures share space and compete for resources.

For example, orcs that dwell in the mines of a ruined dwarf citadel might skirmish constantly against the hobgoblins that hold the citadel’s upper tiers. Mind flayers that have established a colony in the lowest levels of the mines could manipulate and dominate key hobgoblins in an attempt to wipe out the orcs. And all the while, a hidden cell of drow scouts watches and plots to slay the mind flayers, then enslave whatever creatures are left.

It’s easy to think of a dungeon as a collection of encounters, with the adventurers kicking down door after door and killing whatever lies beyond. But the ebb and flow of power between groups in a dungeon provides plenty of opportunities for more subtle interaction. Dungeon denizens are used to striking unlikely alliances, and adventurers are a wild card that canny monsters seek to exploit.

Intelligent creatures in a dungeon have goals, whether as simple as short-term survival or as ambitious as claiming the entire dungeon as the first step in founding an empire. Such creatures might approach adventurers with an offer of alliance, hoping to prevent the characters from laying waste to their lair and to secure aid against their enemies. Bring the NPC leaders of such groups to life as described in chapter 4, fleshing out their personalities, goals, and ideals. Then use those elements to shape a response to the arrival of adventurers in their territory.

Dungeon Ecology

An inhabited dungeon has its own ecosystem. The creatures that live there need to eat, drink, breathe, and sleep, just as creatures in the wilderness do. Predators need to be able to seek prey, and intelligent creatures search for lairs offering the best combination of air, food, water, and security. Keep these factors in mind when designing a dungeon you want the players to believe in. If a dungeon doesn’t have some internal logic to it, adventurers will find it difficult to make reasonable decisions within that environment.

For example, characters who find a pool of fresh water in a dungeon might make the logical assumption that many of the creatures inhabiting the dungeon come to that spot to drink. The adventurers might set an ambush at the pool. Likewise, locked doors — or even doors that require hands to open — can restrict the movement of some creatures. If all the doors in a dungeon are closed, the players might wonder how the carrion crawlers or stirges they repeatedly encounter manage to survive.

Encounter Difficulty

You might be inclined to increase the encounter difficulty as the adventurers descend deeper into the dungeon, as a way to keep the dungeon challenging as the characters gain levels or to ratchet up the tension. However, this approach can turn the dungeon into a grind. A better approach is to include encounters of varying difficulty throughout. The contrast between easy and hard encounters, as well as simple and complex encounters, encourages characters to vary their tactics and keeps the encounters from seeming too similar.

Walls

Some dungeons have walls of masonry. Others have walls of solid rock, hewn with tools to give them a rough, chiseled look, or worn smooth by the passage of water or lava. An aboveground dungeon might be made of wood or composite materials.

Walls are sometimes adorned with murals, frescoes, bas-reliefs, and lighting fixtures such as sconces or torch brackets. A few even have secret doors built into them.

Doors

Dungeon doorways might be set within plain arches and lintels. They might be festooned with carvings of gargoyles or leering faces or engraved with sigils that reveal clues as to what lies beyond.

Stuck Doors. Dungeon doors often become stuck when not used frequently. Opening a stuck door requires a successful Strength check. Chapter 8, “Running the Game,” provides guidelines for setting the DC.

Locked Doors. Characters who don’t have the key to a locked door can pick the lock with a successful Dexterity check (doing so requires thieves’ tools and proficiency in their use). They can also force the door with a successful Strength check, smash the door to pieces by dealing enough damage to it, or use a knock spell or similar magic. Chapter 8 provides guidelines for setting the DCs and assigning statistics to doors and other objects.

Barred Doors. A barred door is similar to a locked door, except that there’s no lock to pick, and the door can be opened normally from the barred side by using an action to lift the bar from its braces.

Secret Doors

A secret door is crafted to blend into the wall that surrounds it. Sometimes faint cracks in the wall or scuff marks on the floor betray the secret door’s presence.

Detecting a Secret Door. Use the characters’ passive Wisdom (Perception) scores to determine whether anyone in the party notices a secret door without actively searching for it. Characters can also find a secret door by actively searching the location where the door is hidden and succeeding on a Wisdom (Perception) check. To set an appropriate DC for the check, see chapter 8.

Opening a Secret Door. Once a secret door is detected, a successful Intelligence (Investigation) check might be required to determine how to open it if the opening mechanism isn’t obvious. Set the DC according to the difficulty guidelines in chapter 8.

If adventurers can’t determine how to open a secret door, breaking it down is always an option. Treat it as a locked door made of the same material as the surrounding wall, and use the guidelines in the Running the Game section to determine appropriate DCs or statistics.

Concealed Doors

A concealed door is a normal door that is hidden from view. A secret door is carefully crafted to blend into its surrounding surface, whereas a concealed door is most often hidden by mundane means. It might be covered by a tapestry, covered with plaster, or (in the case of a concealed trapdoor) hidden under a rug. Normally, no ability check is required to find a concealed door. A character need only look in the right place or take the right steps to reveal the door. However, you can use the characters’ passive Wisdom (Perception) scores to determine whether any of them notices tracks or signs of a tapestry or rug having been recently disturbed.

Portcullises

A portcullis is a set of vertical bars made of wood or iron, reinforced with one or more horizontal bands. It blocks a passage or archway until it is raised up into the ceiling by a winch and chain. The main benefit of a portcullis is that it blocks a passage while still allowing guards to watch the area beyond and make ranged attacks or cast spells through it.

Winching a portcullis up or down requires an action. If a character can’t reach the winch (usually because it is on the other side of the portcullis), lifting the portcullis or bending its bars far enough apart to pass through them requires a successful Strength check. The DC of the check depends on the size and weight of the portcullis or the thickness of its bars. To determine an appropriate DC, see chapter 8.

Darkness and Light

Darkness is the default condition inside an underground complex or in the interior of aboveground ruins, but an inhabited dungeon might have light sources.

In subterranean settlements, even races that have darkvision use fire for warmth, cooking, and defense. But many creatures have no need of warmth or light. Adventurers must bring their own sources of light into dusty tombs where only undead stand guard, abandoned ruins teeming with predatory monsters and oozes, and natural caverns where sightless creatures hunt.

The light of a torch or lantern helps a character see over a short distance, but other creatures can see that light source from far away. Bright light in an environment of total darkness can be visible for miles, though a clear line of sight over such a distance is rare underground. Even so, adventurers using light sources in a dungeon often attract monsters, just as dungeon features that shed light (from phosphorescent fungi to the glow of magical portals) can draw adventurers’ attention.

Air Quality

Subterranean tunnels and aboveground ruins are often enclosed spaces with little airflow. Though it’s rare for a dungeon to be sealed so tightly that adventurers have trouble breathing, the atmosphere is often stifling and oppressive. What’s more, odors linger in a dungeon and can be magnified by the stillness of the atmosphere.

Sounds

A dungeon’s enclosed geography helps channel sound. The groaning creak of an opening door can echo down hundreds of feet of passageway. Louder noises such as the clanging hammers of a forge or the din of battle can reverberate through an entire dungeon. Many creatures that live underground use such sounds as a way of locating prey, or go on alert at any sound of an adventuring party’s intrusion.

Brown Mold

Brown mold feeds on warmth, drawing heat from anything around it. A patch of brown mold typically covers a 10-foot square, and the temperature within 30 feet of it is always frigid.

When a creature moves to within 5 feet of the mold for the first time on a turn or starts its turn there, it must make a DC 12 Constitution saving throw, taking 22 (4d10) cold damage on a failed save, or half as much damage on a successful one.

Brown mold is immune to fire, and any source of fire brought within 5 feet of a patch causes it to instantly expand outward in the direction of the fire, covering a 10-foot-square area (with the source of the fire at the center of that area). A patch of brown mold exposed to an effect that deals cold damage is instantly destroyed.

Green Slime

This acidic slime devours flesh, organic material, and metal on contact. Bright green, wet, and sticky, it clings to walls, floors, and ceilings in patches.

A patch of green slime covers a 5-foot square, has blindsight out to a range of 30 feet, and drops from walls and ceilings when it detects movement below it. Beyond that, it has no ability to move. A creature aware of the slime’s presence can avoid being struck by it with a successful DC 10 Dexterity saving throw. Otherwise, the slime can’t be avoided as it drops.

A creature that comes into contact with green slime takes 5 (1d10) acid damage. The creature takes the damage again at the start of each of its turns until the slime is scraped off or destroyed. Against wood or metal, green slime deals 11 (2d10) acid damage each round, and any nonmagical wood or metal weapon or tool used to scrape off the slime is effectively destroyed.

Sunlight, any effect that cures disease, and any effect that deals cold, fire, or radiant damage destroys a patch of green slime.

Webs

Giant spiders weave thick, sticky webs across passages and at the bottom of pits to snare prey. These web-filled areas are difficult terrain. Moreover, a creature entering a webbed area for the first time on a turn or starting its turn there must succeed on a DC 12 Dexterity saving throw or become restrained by the webs. A restrained creature can use its action to try to escape, doing so with a successful DC 12 Strength (Athletics) or Dexterity (Acrobatics) check.

Each 10-foot cube of giant webs has AC 10, 15 hit points, vulnerability to fire, and immunity to bludgeoning, piercing, and psychic damage.

Yellow Mold

Yellow mold grows in dark places, and one patch covers a 5-foot square. If touched, the mold ejects a cloud of spores that fills a 10-foot cube originating from the mold. Any creature in the area must succeed on a DC 15 Constitution saving throw or take 11 (2d10) poison damage and become poisoned for 1 minute. While poisoned in this way, the creature takes 5 (1d10) poison damage at the start of each of its turns. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a successful save.

Sunlight or any amount of fire damage instantly destroys one patch of yellow mold.

Monster Lairs

A wilderness area approximately 50 miles across can support roughly a half-dozen monster lairs, but probably no more than one apex predator such as a dragon.

If you expect the characters to explore a monster’s lair, you’ll need to find or create an appropriate map for the lair and stock the lair as you would a dungeon.

Monuments

In places where civilization rules or once ruled, adventurers might find monuments built to honor great leaders, gods, and cultures. Use the Monuments table for inspiration, or randomly roll to determine what monument the adventurers stumble upon.

Ruins

Crumbling towers, ancient temples, and razed cities are perfect sites for adventures. Additionally, noting the existence of an old, crumbling wall that runs alongside a road, a sagging stone windmill on a hilltop, or a jumble of standing stones can add texture to your wilderness.

Settlements

Settlements exist in places where food, water, farmland, and building materials are abundant. A civilized province roughly 50 miles across might have one city, a few rural towns, and a scattering of villages and trading posts. An uncivilized area might have a single trading post that stands at the edge of a wild frontier, but no larger settlements.

In addition to settlements, a province might contain ruined villages and towns that are either abandoned or serve as lairs for marauding bandits and monsters.

Strongholds

Strongholds provide the local population with protection in times of trouble. The number of strongholds in an area depends on the dominant society, the population, the strategic importance or vulnerability of the region, and the wealth of the land.

Weird Locales

Weird locales make the fantastic and the supernatural an intrinsic part of your wilderness adventures.

Extreme Cold

Whenever the temperature is at or below 0 degrees Fahrenheit, a creature exposed to the cold must succeed on a DC 10 Constitution saving throw at the end of each hour or gain one level of exhaustion. Creatures with resistance or immunity to cold damage automatically succeed on the saving throw, as do creatures wearing cold weather gear (thick coats, gloves, and the like) and creatures naturally adapted to cold climates.

Extreme Heat

When the temperature is at or above 100 degrees Fahrenheit, a creature exposed to the heat and without access to drinkable water must succeed on a Constitution saving throw at the end of each hour or gain one level of exhaustion. The DC is 5 for the first hour and increases by 1 for each additional hour. Creatures wearing medium or heavy armor, or who are clad in heavy clothing, have disadvantage on the saving throw. Creatures with resistance or immunity to fire damage automatically succeed on the saving throw, as do creatures naturally adapted to hot climates.

Strong Wind

A strong wind imposes disadvantage on ranged weapon attack rolls and Wisdom (Perception) checks that rely on hearing. A strong wind also extinguishes open flames, disperses fog, and makes flying by nonmagical means nearly impossible. A flying creature in a strong wind must land at the end of its turn or fall.

A strong wind in a desert can create a sandstorm that imposes disadvantage on Wisdom (Perception) checks that rely on sight.

Heavy Precipitation

Everything within an area of heavy rain or heavy snowfall is lightly obscured, and creatures in the area have disadvantage on Wisdom (Perception) checks that rely on sight. Heavy rain also extinguishes open flames and imposes disadvantage on Wisdom (Perception) checks that rely on hearing.

Desecrated Ground

Some cemeteries and catacombs are imbued with the unseen traces of ancient evil. An area of desecrated ground can be any size, and a detect evil and good spell cast within range reveals its presence.

Undead standing on desecrated ground have advantage on all saving throws.

A vial of holy water purifies a 10-foot-square area of desecrated ground when sprinkled on it, and a hallow spell purifies desecrated ground within its area.

Frigid Water

A creature can be immersed in frigid water for a number of minutes equal to its Constitution score before suffering any ill effects. Each additional minute spent in frigid water requires the creature to succeed on a DC 10 Constitution saving throw or gain one level of exhaustion. Creatures with resistance or immunity to cold damage automatically succeed on the saving throw, as do creatures that are naturally adapted to living in ice-cold water.

Quicksand

A quicksand pit covers the ground in roughly a 10-foot-square area and is usually 10 feet deep. When a creature enters the area, it sinks 1d4 + 1 feet into the quicksand and becomes restrained. At the start of each of the creature’s turns, it sinks another 1d4 feet. As long as the creature isn’t completely submerged in quicksand, it can escape by using its action and succeeding on a Strength check. The DC is 10 plus the number of feet the creature has sunk into the quicksand. A creature that is completely submerged in quicksand can’t breathe (see the suffocation rules in the Player’s Handbook).

A creature can pull another creature within its reach out of a quicksand pit by using its action and succeeding on a Strength check. The DC is 5 plus the number of feet the target creature has sunk into the quicksand.

Razorvine

Razorvine is a plant that grows in wild tangles and hedges. It also clings to the sides of buildings and other surfaces as ivy does. A 10-foot-high, 10-foot-wide, 5-foot-thick wall or hedge of razorvine has AC 11, 25 hit points, and immunity to bludgeoning, piercing, and psychic damage.

When a creature comes into direct contact with razorvine for the first time on a turn, the creature must succeed on a DC 10 Dexterity saving throw or take 5 (1d10) slashing damage from the razorvine’s bladelike thorns.

Slippery Ice

Slippery ice is difficult terrain. When a creature moves onto slippery ice for the first time on a turn, it must succeed on a DC 10 Dexterity (Acrobatics) check or fall prone.

Thin Ice

Thin ice has a weight tolerance of 3d10 × 10 pounds per 10-foot-square area. Whenever the total weight on an area of thin ice exceeds its tolerance, the ice in that area breaks. All creatures on broken ice fall through.

Food and Water

The food and water requirements noted in the Player’s Handbook are for characters. Horses and other creatures require different quantities of food and water per day based on their size. Water needs are doubled if the weather is hot.

Food and Water Needs

Wilderness Navigation

Race Relations

Ruler’s Status

Notable Traits

Known For Its…

Current Calamity

Building Type

Residence

Religious Building

Tavern

Tavern Name Generator

Warehouse

Shop

Trials

In most settlements, trials are overseen by magistrates or local lords. Some trials are argued, with the conflicting parties or their advocates presenting precedent and evidence until the judge makes a decision, with or without the aid of spells or interrogation. Others are decided with a trial by ordeal or trial by combat. If the evidence against the accused is overwhelming, a magistrate or local lord can forgo a trial and skip right to the sentencing.

Sentences

A settlement might have a jail to hold accused criminals awaiting trial, but few settlements have prisons to incarcerate convicted criminals. A person found guilty of a crime is usually fined, condemned to forced labor for a period of several months or years, exiled, or executed, depending on the magnitude of the crime.

Random Undersea Encounters

You can check for random undersea encounters as often as you would check for them on land (see chapter 3). The Random Undersea Encounters table presents several intriguing options. You can either roll on the table for a random result or choose whichever one works best.

Swimming

Unless aided by magic, a character can’t swim for a full 8 hours per day. After each hour of swimming, a character must succeed on a DC 10 Constitution saving throw or gain one level of exhaustion.

A creature that has a swimming speed — including a character with a ring of swimming or similar magic — can swim all day without penalty and uses the normal forced march rules in the Player’s Handbook.

Swimming through deep water is similar to traveling at high altitudes, because of the water’s pressure and cold temperature. For a creature without a swimming speed, each hour spent swimming at a depth greater than 100 feet counts as 2 hours for the purpose of determining exhaustion. Swimming for an hour at a depth greater than 200 feet counts as 4 hours.

Underwater Visibility

Visibility underwater depends on water clarity and the available light. Unless the characters have light sources, use the Underwater Encounter Distance table to determine the distance at which characters underwater become aware of a possible encounter.

Underwater Encounter Distance

Navigation

Seagoing vessels stay close to shore when they can, because navigation is easier when landmarks are visible. As long as a ship is within sight of land, there is no chance of the vessel becoming lost. Otherwise, a ship’s navigator must rely on dead reckoning (tracking the direction and distance of the ship’s travel) or the sun and the stars.

Use the Wilderness Navigation table earlier in this chapter to determine whether a ship veers off course.

Random Encounters at Sea

You can check for random encounters at sea as often as you would check for them on land (see chapter 3 for more information). The Random Encounters at Sea table presents a number of options and ideas.

SHIPWRECKS

A shipwreck is a plot device that can be used sparingly to great effect, particularly if you want the characters to be washed ashore on some monster-infested island or (in the case of an airship) dropped in the middle of some exotic land. There aren’t rules for determining when a shipwreck happens; it happens when you want or need it to happen.

Even the strongest seafaring ship can founder in a storm, run aground on rocks or reefs, sink during a pirate attack, or be dragged underwater by a sea monster. A storm or hungry dragon can lay waste to an airship just as easily. A shipwreck has the potential to change the direction of a campaign. It isn’t, however, a particularly good way to kill off characters or end a campaign.

If you and your campaign conspire to wreck a ship on which the characters are traveling, it is assumed that the characters survive with the equipment they were wearing or carrying still in their possession. The fate of any NPCs and cargo aboard the wrecked ship is entirely up to you.

Weather at Sea

Use the Weather table earlier in this chapter when checking for weather at sea.

If weather conditions indicate both a strong wind and heavy rain, they combine to create a storm with high waves. A crew caught in a storm loses sight of all landmarks (unless there’s a lighthouse or other bright feature), and ability checks made to navigate during the storm have disadvantage.

In a dead calm (no wind), ships can’t move under sail and must be rowed. A ship sailing against a strong wind moves at half speed.

Visibility

A relatively calm sea offers great visibility. From a crow’s nest, a lookout can spot another ship or a coastline up to 10 miles away, assuming clear skies. Overcast skies reduce that distance by half. Rain and fog reduce visibility just as they do on land.

Owning a Ship

At some point in your campaign, the adventurers might gain custody of a ship. They might purchase or capture one or receive one to carry out a mission. It’s up to you whether a ship is available for purchase, and you have the power to deprive the adventurers of a ship at any time should it become a nuisance (see the “Shipwrecks” sidebar).

Crew. A ship needs a crew of skilled hirelings to function. As per the Player’s Handbook, one skilled hireling costs at least 2 gp per day. The minimum number of skilled hirelings needed to crew a ship depends on the type of vessel, as shown in the Airborne and Waterborne Vehicles table.

You can track the loyalty of individual crew members or the crew as a whole using the optional loyalty rules in chapter 4. If at least half the crew becomes disloyal during a voyage, the crew turns hostile and stages a mutiny. If the ship is berthed, disloyal crew members leave the ship and never return.

Passengers. The table indicates the number of Small and Medium passengers the ship can accommodate. Accommodations consist of shared hammocks in tight quarters. A ship outfitted with private accommodations can carry one-fifth as many passengers.

A passenger is usually expected to pay 5 sp per day for a hammock, but prices can vary from ship to ship. A small private cabin usually costs 2 gp per day.

Cargo. The table indicates the maximum tonnage each kind of ship can carry.

Damage Threshold. A ship has immunity to all damage unless it takes an amount of damage equal to or greater than its damage threshold, in which case it takes damage as normal. Any damage that fails to meet or exceed the damage threshold is considered superficial and doesn’t reduce the ship’s hit points.

Ship Repair. Repairs to a damaged ship can be made while the vessel is berthed. Repairing 1 hit point of damage requires 1 day and costs 20 gp for materials and labor.

Airborne and Waterborne Vehicles

Triggering a Trap

Most traps are triggered when a creature goes somewhere or touches something that the trap’s creator wanted to protect. Common triggers include stepping on a pressure plate or a false section of floor, pulling a trip wire, turning a doorknob, and using the wrong key in a lock. Magic traps are often set to go off when a creature enters an area or touches an object. Some magic traps (such as the glyph of warding spell) have more complicated trigger conditions, including a password that prevents the trap from activating.

Detecting and Disabling a Trap

Usually, some element of a trap is visible to careful inspection. Characters might notice an uneven flagstone that conceals a pressure plate, spot the gleam of light off a trip wire, notice small holes in the walls from which jets of flame will erupt, or otherwise detect something that points to a trap’s presence.

A trap’s description specifies the checks and DCs needed to detect it, disable it, or both. A character actively looking for a trap can attempt a Wisdom (Perception) check against the trap’s DC. You can also compare the DC to detect the trap with each character’s passive Wisdom (Perception) score to determine whether anyone in the party notices the trap in passing. If the adventurers detect a trap before triggering it, they might be able to disarm it, either permanently or long enough to move past it. You might call for an Intelligence (Investigation) check for a character to deduce what needs to be done, followed by a Dexterity check using thieves’ tools to perform the necessary sabotage.

Any character can attempt an Intelligence (Arcana) check to detect or disarm a magic trap, in addition to any other checks noted in the trap’s description. The DCs are the same regardless of the check used. In addition, dispel magic has a chance of disabling most magic traps. A magic trap’s description provides the DC for the ability check made when you use dispel magic.

In most cases, a trap’s description is clear enough that you can adjudicate whether a character’s actions locate or foil the trap. As with many situations, you shouldn’t allow die rolling to override clever play and good planning. Use your common sense, drawing on the trap’s description to determine what happens. No trap’s design can anticipate every possible action that the characters might attempt.

You should allow a character to discover a trap without making an ability check if an action would clearly reveal the trap’s presence. For example, if a character lifts a rug that conceals a pressure plate, the character has found the trigger and no check is required.

Foiling traps can be a little more complicated. Consider a trapped treasure chest. If the chest is opened without first pulling on the two handles set in its sides, a mechanism inside fires a hail of poison needles toward anyone in front of it. After inspecting the chest and making a few checks, the characters are still unsure if it’s trapped. Rather than simply open the chest, they prop a shield in front of it and push the chest open at a distance with an iron rod. In this case, the trap still triggers, but the hail of needles fires harmlessly into the shield.

Traps are often designed with mechanisms that allow them to be disarmed or bypassed. Intelligent monsters that place traps in or around their lairs need ways to get past those traps without harming themselves. Such traps might have hidden levers that disable their triggers, or a secret door might conceal a passage that goes around the trap.

Trap Effects

The effects of traps can range from inconvenient to deadly, making use of elements such as arrows, spikes, blades, poison, toxic gas, blasts of fire, and deep pits. The deadliest traps combine multiple elements to kill, injure, contain, or drive off any creature unfortunate enough to trigger them. A trap’s description specifies what happens when it is triggered.

The attack bonus of a trap, the save DC to resist its effects, and the damage it deals can vary depending on the trap’s severity. Use the Trap Save DCs and Attack Bonuses table and the Damage Severity by Level table for suggestions based on three levels of trap severity.

A trap intended to be a setback is unlikely to kill or seriously harm characters of the indicated levels, whereas a dangerous trap is likely to seriously injure (and potentially kill) characters of the indicated levels. A deadly trap is likely to kill characters of the indicated levels.

Trap Save DCs and Attack Bonuses

Damage Severity by Level

Complex Traps

Complex traps work like standard traps, except once activated they execute a series of actions each round. A complex trap turns the process of dealing with a trap into something more like a combat encounter.

When a complex trap activates, it rolls initiative. The trap’s description includes an initiative bonus. On its turn, the trap activates again, often taking an action. It might make successive attacks against intruders, create an effect that changes over time, or otherwise produce a dynamic challenge. Otherwise, the complex trap can be detected and disabled or bypassed in the usual ways.

For example, a trap that causes a room to slowly flood works best as a complex trap. On the trap’s turn, the water level rises. After several rounds, the room is completely flooded.

Collapsing Roof

Mechanical trap

This trap uses a trip wire to collapse the supports keeping an unstable section of a ceiling in place.

The trip wire is 3 inches off the ground and stretches between two support beams. The DC to spot the trip wire is 10. A successful DC 15 Dexterity check using thieves’ tools disables the trip wire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Anyone who inspects the beams can easily determine that they are merely wedged in place. As an action, a character can knock over a beam, causing the trap to trigger.

The ceiling above the trip wire is in bad repair, and anyone who can see it can tell that it’s in danger of collapse.

When the trap is triggered, the unstable ceiling collapses. Any creature in the area beneath the unstable section must succeed on a DC 15 Dexterity saving throw, taking 22 (4d10) bludgeoning damage on a failed save, or half as much damage on a successful one. Once the trap is triggered, the floor of the area is filled with rubble and becomes difficult terrain.

Falling Net

Mechanical trap

This trap uses a trip wire to release a net suspended from the ceiling.

The trip wire is 3 inches off the ground and stretches between two columns or trees. The net is hidden by cobwebs or foliage. The DC to spot the trip wire and net is 10. A successful DC 15 Dexterity check using thieves’ tools breaks the trip wire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

When the trap is triggered, the net is released, covering a 10-foot-square area. Those in the area are trapped under the net and restrained, and those that fail a DC 10 Strength saving throw are also knocked prone. A creature can use its action to make a DC 10 Strength check, freeing itself or another creature within its reach on a success. The net has AC 10 and 20 hit points. Dealing 5 slashing damage to the net (AC 10) destroys a 5-foot-square section of it, freeing any creature trapped in that section.

Fire-Breathing Statue

Magic trap

This trap is activated when an intruder steps on a hidden pressure plate, releasing a magical gout of flame from a nearby statue. The statue can be of anything, including a dragon or a wizard casting a spell.

The DC is 15 to spot the pressure plate, as well as faint scorch marks on the floor and walls. A spell or other effect that can sense the presence of magic, such as detect magic, reveals an aura of evocation magic around the statue.

The trap activates when more than 20 pounds of weight is placed on the pressure plate, causing the statue to release a 30-foot cone of fire. Each creature in the fire must make a DC 13 Dexterity saving throw, taking 22 (4d10) fire damage on a failed save, or half as much damage on a successful one.

Wedging an iron spike or other object under the pressure plate prevents the trap from activating. A successful dispel magic (DC 13) cast on the statue destroys the trap.

Pits

Mechanical trap

Four basic pit traps are presented here.

Simple Pit. A simple pit trap is a hole dug in the ground. The hole is covered by a large cloth anchored on the pit’s edge and camouflaged with dirt and debris.

The DC to spot the pit is 10. Anyone stepping on the cloth falls through and pulls the cloth down into the pit, taking damage based on the pit’s depth (usually 10 feet, but some pits are deeper).

Hidden Pit. This pit has a cover constructed from material identical to the floor around it.

A successful DC 15 Wisdom (Perception) check discerns an absence of foot traffic over the section of floor that forms the pit’s cover. A successful DC 15 Intelligence (Investigation) check is necessary to confirm that the trapped section of floor is actually the cover of a pit.

When a creature steps on the cover, it swings open like a trapdoor, causing the intruder to spill into the pit below. The pit is usually 10 or 20 feet deep but can be deeper.

Once the pit trap is detected, an iron spike or similar object can be wedged between the pit’s cover and the surrounding floor in such a way as to prevent the cover from opening, thereby making it safe to cross. The cover can also be magically held shut using the arcane lock spell or similar magic.

Locking Pit. This pit trap is identical to a hidden pit trap, with one key exception: the trap door that covers the pit is spring-loaded. After a creature falls into the pit, the cover snaps shut to trap its victim inside.

A successful DC 20 Strength check is necessary to pry the cover open. The cover can also be smashed open (determine the cover’s statistics using the guidelines in chapter 8. A character in the pit can also attempt to disable the spring mechanism from the inside with a DC 15 Dexterity check using thieves’ tools, provided that the mechanism can be reached and the character can see. In some cases, a mechanism (usually hidden behind a secret door nearby) opens the pit.

Spiked Pit. This pit trap is a simple, hidden, or locking pit trap with sharpened wooden or iron spikes at the bottom. A creature falling into the pit takes 11 (2d10) piercing damage from the spikes, in addition to any falling damage. Even nastier versions have poison smeared on the spikes. In that case, anyone taking piercing damage from the spikes must also make a DC 13 Constitution saving throw, taking an 22 (4d10) poison damage on a failed save, or half as much damage on a successful one.

Poison Darts

Mechanical trap

When a creature steps on a hidden pressure plate, poison-tipped darts shoot from spring-loaded or pressurized tubes cleverly embedded in the surrounding walls. An area might include multiple pressure plates, each one rigged to its own set of darts.

The tiny holes in the walls are obscured by dust and cobwebs, or cleverly hidden amid bas-reliefs, murals, or frescoes that adorn the walls. The DC to spot them is 15. With a successful DC 15 Intelligence (Investigation) check, a character can deduce the presence of the pressure plate from variations in the mortar and stone used to create it, compared to the surrounding floor. Wedging an iron spike or other object under the pressure plate prevents the trap from activating. Stuffing the holes with cloth or wax prevents the darts contained within from launching.

The trap activates when more than 20 pounds of weight is placed on the pressure plate, releasing four darts. Each dart makes a ranged attack with a +8 bonus against a random target within 10 feet of the pressure plate (vision is irrelevant to this attack roll). (If there are no targets in the area, the darts don’t hit anything.) A target that is hit takes 2 (1d4) piercing damage and must succeed on a DC 15 Constitution saving throw, taking 11 (2d10) poison damage on a failed save, or half as much damage on a successful one.

Poison Needle

Mechanical trap

A poisoned needle is hidden within a treasure chest’s lock, or in something else that a creature might open. Opening the chest without the proper key causes the needle to spring out, delivering a dose of poison.

When the trap is triggered, the needle extends 3 inches straight out from the lock. A creature within range takes 1 piercing damage and 11 (2d10) poison damage, and must succeed on a DC 15 Constitution saving throw or be poisoned for 1 hour.

A successful DC 20 Intelligence (Investigation) check allows a character to deduce the trap’s presence from alterations made to the lock to accommodate the needle. A successful DC 15 Dexterity check using thieves’ tools disarms the trap, removing the needle from the lock. Unsuccessfully attempting to pick the lock triggers the trap.

Rolling Sphere

Mechanical trap

When 20 or more pounds of pressure are placed on this trap’s pressure plate, a hidden trapdoor in the ceiling opens, releasing a 10-foot-diameter rolling sphere of solid stone.

With a successful DC 15 Wisdom (Perception) check, a character can spot the trapdoor and pressure plate. A search of the floor accompanied by a successful DC 15 Intelligence (Investigation) check reveals variations in the mortar and stone that betray the pressure plate’s presence. The same check made while inspecting the ceiling notes variations in the stonework that reveal the trapdoor. Wedging an iron spike or other object under the pressure plate prevents the trap from activating.

Activation of the sphere requires all creatures present to roll initiative. The sphere rolls initiative with a +8 bonus. On its turn, it moves 60 feet in a straight line. The sphere can move through creatures’ spaces, and creatures can move through its space, treating it as difficult terrain. Whenever the sphere enters a creature’s space or a creature enters its space while it’s rolling, that creature must succeed on a DC 15 Dexterity saving throw or take 55 (10d10) bludgeoning damage and be knocked prone.

The sphere stops when it hits a wall or similar barrier. It can’t go around corners, but smart dungeon builders incorporate gentle, curving turns into nearby passages that allow the sphere to keep moving.

As an action, a creature within 5 feet of the sphere can attempt to slow it down with a DC 20 Strength check. On a successful check, the sphere’s speed is reduced by 15 feet. If the sphere’s speed drops to 0, it stops moving and is no longer a threat.

Sphere of Annihilation

Magic trap

Magical, impenetrable darkness fills the gaping mouth of a stone face carved into a wall. The mouth is 2 feet in diameter and roughly circular. No sound issues from it, no light can illuminate the inside of it, and any matter that enters it is instantly obliterated.

A successful DC 20 Intelligence (Arcana) check reveals that the mouth contains a sphere of annihilation that can’t be controlled or moved. It is otherwise identical to a normal sphere of annihilation, as described in chapter 7, “Treasure.”

Some versions of the trap include an enchantment placed on the stone face, such that specified creatures feel an overwhelming urge to approach it and crawl inside its mouth. This effect is otherwise like the sympathy aspect of the antipathy/sympathy spell. A successful dispel magic (DC 18) removes this enchantment.