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In NetHack, traps are mechanisms on a space which may activate when you or a monster steps on them. There are many types of traps and a wide assortment of effects that they can cause, most of them negative. Many traps affect monsters, including pets, differently than they affect you - some traps cannot even be triggered by monsters.

Traps can be detected through various methods:

Certain types of traps can be disarmed with the #untrap command.


In both filler levels and most special levels, a "random" trap is selected uniformly from the whole set of eligible traps, subject to level difficulty checks and some exclusions; see below.[1] Oddly, special levels that contain maze filler (the Castle, Asmodeus, Baalzebub, Orcus, and all real and fake Wizard's Tower levels, but not the Big Room or the Catacombs) use a completely separate formula that ignores level difficulty for selecting traps in the mazes.[2] It nonetheless ends up working much the same way overall, but actually makes fire traps less common than they would otherwise be in Gehennom on those levels.

Certain types of traps up to dungeon level 4 may have a pre-aged corpse generated on top, along with random cursed weapons, tools, food or gems. These are often referred to as fake bones, referring to their similarity to bones files. The chance is 1 − Dlvl − 14, meaning that every eligible trap will have a corpse and items on the first floor.[3] There will always be at least one possession, and there is a 20% chance of placing an additional possession after each one.[4] Squeaky boards and rust traps never have a corpse because they are non-lethal, and pits or holes also never generate a corpse; any corpses found in pits are usually from generated monsters that fell in, especially if their associated items are present (e.g. finding an orcish helm with a goblin corpse).

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

While hallucinating, traps may appear on the map and in messages as random or nonexistent trap types, though any messages resulting from triggering the trap are unchanged.

Anti-magic field

^ anti-magic field Anti-magic field.png
Generates Anywhere
Effect Pw loss, or HP loss if magic resistant

Anti-magic fields drain between 2 and your experience level + 1 points of your spell power. If this would cause your spell power to go below zero, your maximum spell power will be permanently reduced by that amount, and your spell power becomes zero.[5] Anti-magic fields have no effect on your maximum spell power if it is zero.

If you have magic resistance, you take damage instead of losing power. The damage is at least d4, with an additional d4 each if you:

If you have phasing, you take 14 as much damage, rounded up.

Monsters that have a special attack such as spellcasting or a breath weapon will also be affected by this trap. The timeout for their special attack increases by 2d2 turns unless they are magic resistant, in which case they lose HP. This will also reveal the trap. Other monsters do not trigger this trap and do not reveal it when they pass over it.

You feel your magical energy drain away.
You are not magic resistant, and your Pw was drained.
You feel momentarily lethargic.
You are not magic resistant, but you have zero maximum Pw to drain.
You feel sluggish.
You are magic resistant, and took less than 14 your HP as damage.
You feel very lethargic.
You are magic resistant, and took more than 14 your HP as damage.
You feel unbearably torpid!
You are magic resistant, and were killed by HP loss.
<monster> seems lethargic.
A monster lost some Pw from an anti-magic field.
<monster> is killed by the compression from an anti-magic field!
A magic-resistant monster lost enough HP from an anti-magic field to die.


Arrow trap

^ arrow trap Arrow trap.png
Generates Anywhere
Effect Fires arrows

Arrow traps fire arrows at you or whoever else steps on them, which generally do 1d6 damage.

These traps can be a useful source of arrows. While standing on or adjacent to the square with the trap, successfully untrapping an arrow trap will yield a large supply of arrows (50 − rnl(50)).[7] Each time you or a monster triggers this trap there is a 115 chance that it will disappear. Any arrow that hits you or a monster is guaranteed to be lost. The average number of arrows you obtain by disarming is dependent on luck, but is higher than the average number you obtain by stepping on the trap until it disappears.

To remove: #untrap, or trigger it repeatedly until it runs out of arrows.

An arrow shoots out at you!
You triggered an arrow trap.
<monster> is hit by an arrow!
A monster triggered an arrow trap.
You hear a loud click!
The trap was out of arrows and is now gone.


Bear trap

^ bear trap Bear trap.png
Generates Anywhere
Effect Prevents movement
Main article: Beartrap

A bear trap causes 2d4 damage[9] and renders you immobile for several turns. During this time, you can attack and be attacked, but you cannot move from the spot. When caught in a bear trap, you are unable to kick. For some reason, escaping a bear trap is 5 times more likely when attempting to move diagonally than when attempting to move orthogonally.[10]

If you trigger the trap when riding, it affects your steed instead of you. Monsters can be trapped too.[11]

It is possible to untrap a bear trap. If successful, it will appear as a beartrap, an item which can be picked up. You may then apply it to a new location. If unsuccessful, you will become trapped. If a bugbear or an owlbear gets stuck in a bear trap outside your sight, then you will hear "the roaring of an angry bear". If you are caught in a bear trap, you cannot untrap yourself.

Oddly, beartraps reset themselves.

To remove: #untrap, or eat the trap as a metallivore.

Dart trap

^ dart trap Dart trap.png
Generates Anywhere
Effect Fires darts

A dart trap is similar to an arrow trap, but it fires darts. Darts will generally do 1d3 damage. Darts have a 1 in 5 chance of being poisoned, so be careful.

Disarming a dart trap will recover a large stack of darts, but this should probably not be attempted by characters lacking poison resistance. Like arrow traps, dart traps have a 115 chance of disappearing each time they are triggered; darts that hit always disappear; and you will obtain more darts by disarming than by triggering it (on average 50 − rnl(50) darts).[12]

To remove: #untrap, or trigger it repeatedly until it runs out of darts ("You hear a soft click.")

A little dart shoots out at you!
You triggered a dart trap.
<monster> is hit by a dart!
A monster triggered a dart trap.
You hear a soft click.
The trap was out of darts and is now gone.


Fire trap

^ fire trap Fire trap.png
Generates Gehennom, mazes, some quests, Plane of Fire
Effect Deals fire damage, burns inventory

A fire trap creates a column of flame underneath you. If you lack fire resistance, you take 2d4 damage, and your maximum HP is reduced by between zero and the damage you took. If you are fire-resistant, you lose 0 or 1 HP, and your maximum HP is unaffected.

The trap will attempt to burn an article of clothing with an equal chance of each of 5 types (helm, torso, shield, gloves, or boots) being selected. If the selected armor is not torso, but is either fireproof, thoroughly burnt, or not worn, a different type of armor will be selected. If blessed, the chance of the selected armor burning is subject to luck consideration. If the final armor selection is not body armor (regardless of whether the armor survived the luck roll), there is a 13 chance that scrolls, potions, and spellbooks in the main inventory will not be subject to burning. Otherwise all scrolls, potions, and spellbooks will have a 13 chance of burning. For this reason, keep them in a container, especially in Gehennom.

Unlike most traps, fire traps will still activate if you jump over them.

Generation: Fire traps are only randomly generated in Gehennom, maze levels (including to the left and right of the Castle), the Plane of Fire, and some quests, notably the Valkyrie quest. In Gehennom, fire trap generation is increased. 20% of all randomly generated traps in Gehennom are guaranteed to be fire traps.

A magic trap or trapped box or chest has a chance of acting as a fire trap even where a fire trap cannot be generated. A magic trap always acts as a fire trap if activated by a monster.

If a fire trap is created on top of ice (which is common in the Valkyrie quest), stepping on it will melt the ice and replace it with a pool of water, potentially resulting in drowning.

To remove: Dig a pit into the ground while standing on the trap, then fill the pit.

A tower of flame erupts from the floor!
You triggered a fire trap.
A cascade of steamy bubbles erupts from the pool!
You triggered a fire trap underwater.
A cascade of steamy bubbles erupts from the box!
You triggered a fire trap on a box, underwater
You smell smoke.
A nearby fire trap that you can't see was triggered.
A tower of flame erupts from the floor under <monster>!
A monster triggered a fire trap within you sight.
You see a tower of flame erupt from the floor!
An invisible monster triggered a fire trap within your sight.


Fire affects certain golems in a slightly different way[14] when it comes to maximum HP loss. These golems take the 2d4 damage, but their maximum HP is affected as follows:

  • Paper golems lose between max HP and max HP (i.e. they are destroyed)
  • Straw golems lose between 0 and either damage taken or 1/2 max HP (whichever is greater)
  • Wood golems lose between 0 and either damage taken or 1/4 max HP (whichever is greater)
  • Leather golems lose between 0 and either damage taken or 1/8 max HP (whichever is greater)

The logic for this is that paper burns the fastest and leather the slowest.



^ hole Hole.png
Generates Diggable-floor levels, reduced chance
Effect Fall to lower level
Main article: Hole

Holes simply drop you down a number of levels. 2–3 levels is a typical fall distance, but there is no upper limit on how many levels it is possible to fall through, although you won't fall beyond the Castle. Monsters never fall more than one floor.[16]

One technique for dealing with this problem is to go down any stairs you encounter and then go back up again immediately. This way, if you should ever fall down to that level you will know where the exit is. A high dexterity stat will reduce your chances of falling down the hole should you accidentally step on it.

The same hole is not guaranteed to lead to the same location, or even the same level, even if an object, monster or pet went through it immediately before you.

Generation: Holes are much less likely to be randomly generated than other eligible types. Only 1 in 7 attempts to randomly place a hole will succeed. Holes cannot be randomly generated on levels with non-diggable floors, such as the vibrating square level or the Castle. If the floor is non-diggable, the hole trap is replaced with a falling rock trap. Holes cannot be generated beneath a boulder. Unlike other traps, holes are always generated visible.

To remove: Push a boulder into it.

There's a gaping hole under you!
You fell into a hole.


Falling rock trap

^ falling rock trap Falling rock trap.png
Generates Anywhere
Effect Drops rocks

Falling rock traps drop a rock on the victim's head, dealing 2d6 damage. If you are wearing some kind of hard hat, the damage is reduced to 2. The rock stays on the ground, so it is possible to use them as a rock source, although the trap will be exhausted eventually (115 chance each time it is triggered).

Early pet deaths are often due to this type of trap, earning it the nicknames "Puppy Pounder" and "Kitty Killer".

To remove: Trigger it repeatedly until it runs out of rocks.


A trapdoor in the ceiling opens and a rock falls on your head!
You triggered a falling rock trap.
<monster> is hit by a rock!
A monster triggered a falling rock trap.
A trapdoor in the sky opens and a rock falls on your head!
The trap is outdoors, e.g. in the Home level of some Quests.

Land mine

^ land mine Land mine.png
Generates level 6+, Fort Ludios
Effect Explodes, creates pit, wounds legs
Main article: Land mine

Land mines are hidden explosives, especially common in Fort Ludios. They explode when triggered, which will do 1-16 damage, wound your legs and leave behind a pit. You may untrap a land mine from an adjacent square, and then pick it up and install it elsewhere, similar to a bear trap.

Monsters have only a 1 in 3 chance of setting off a land mine when they step on one.[19] Flying creatures are even less likely to set one off (and won't ever fall in the resulting pit), although there is still a slim chance that air currents will activate the mine.[20] Land mines can also be set off by rolling boulders.

Any items on the same square as an active land mine will be blasted around the room (or destroyed, if fragile) when it goes off.

A land mine that is triggered adjacent to a body of water like a pool or moat will create a pit that immediately fills with water, likely immersing you in the process.

To remove: #untrap, or just set it off (although the latter will replace it with a pit).


Level teleporter

^ level teleporter Level teleporter.png
Generates level 5+, not non-teleport level
Effect levelports

This teleports you to a random location on a random level. If you have teleport control, then you can specify the level you will go to, unless you are stunned, fainted, paralyzed, or (with a 15 probability) confused. Otherwise, you or monsters activating the trap will be teleported down at most three levels or up at most to the top of the main dungeon, but never down out of the main dungeon, or into the Sanctum before the invocation ritual. In the Endgame, you, monsters with the Amulet, and elementals on their plane cannot level teleport at all. All eligible target levels are equally likely.[22]

After the player has triggered the trap once, it vanishes, whether the teleportation was successful or not. You may remain on the same level and receive the message "You shudder for a moment."

Magic resistance will prevent you, but not monsters, from being teleported ("You feel a wrenching sensation.") Under certain conditions, you can use a normal teleport trap, even if you have magic resistance (see § Teleportation trap for details). However, you cannot do the same with a level teleporter.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

You can now deliberately take a level teleport trap even if you have magic resistance with ctrl + t.

To remove: Set it off personally; it is not removed when a monster triggers it.


Magic portal

^ magic portal Magic portal.png
Generates Never randomly; special levels and branches only
Effect Transports between branches

While this is not damaging at all, the game internally represents it as a trap. Magic portals are used to transport you between dungeon branches, and between the elemental planes.

The game internally creates a temporary magic portal when the player branchports, but it vanishes instantly after the branchport, so it is hidden from the player and can't actually be used as a portal that you can step into and out of.

Unlike other teleporter traps, a portal will still work if you have magic resistance. Its destination is fixed and is not subject to teleport control.

To remove: This trap cannot be removed, although the portal to your quest disappears if you are rejected with prejudice.


Magic trap

^ magic trap Magic trap.png
Generates Anywhere
Effect Various
Main article: Magic trap

Magic traps can have a variety of effects.

Monsters will fail to trigger this trap with 2021 chance, in which case the trap will do nothing and not be revealed to you. If a monster triggers the trap, it will generate a pillar of flame, acting like a fire trap.

To remove: Trigger it repeatedly until it explodes.



^ pit Pit.png
Generates Anywhere
Effect Prevents movement, damage
Main article: Pit

Pits in the ground open up when you walk over them, causing 1–6 damage. This also abuses strength and dexterity. They require 3–7 turns to "climb to the edge" and escape. You may #jump out of a pit or apply a bullwhip to escape. While in the pit, any light source you are carrying will not travel beyond the walls of the pit. Falling into a pit as a pit fiend or a pit viper will generate YAFM.

To remove: Push a boulder into it.


Polymorph trap

^ polymorph trap Polymorph trap.png
Generates level 8+
Effect polymorph
Main article: Polymorph trap

A polymorph trap turns you into another monster for a limited time. Monsters can make use of them, too. However, monsters (including pets) that are polymorphed stay in that form permanently. After a successful polymorph of the player, it vanishes.

Magic resistance will prevent you (and the steed you're riding) from being polymorphed. ("You feel momentarily different.")

To remove: Set it off personally; it is not removed when a pet or monster triggers it.


Rolling boulder trap

^ rolling boulder trap Rolling boulder trap.png
Generates level 2+
Effect Rolls boulder, causes damage

A rolling boulder trap has two parts. The actual trap is a switch which, when activated by stepping on it, sets a nearby boulder rolling toward you. The existence of these traps can sometimes be inferred by an incongruously placed boulder in a room. The path between the boulder and the trap must be clear,[28] though the boulder will pass through some dungeon features like fountains. When it hits another boulder, "you hear a loud crash as a boulder sets another in motion", it stops, and the other boulder begins moving. If a boulder trap is activated but you can't see it, you get the message "you hear rumbling in the distance".

Being hit with the boulder deals you d20 damage.

To remove: Destroy the boulder, move it beside the trap, or move it out of line with the trap, then activate the trap; a boulder trap only activates if there exists a boulder on one of the two designated launch squares, and activating the trap when there is no suitable boulder will destroy it.[29][30]

Click! You trigger a rolling boulder trap!
You triggered a rolling boulder trap.
Click! <monster> triggers something.
A monster triggered a rolling boulder trap.
Fortunately for you, no boulder was released.
There was no boulder in the launch spot for this trap, so the trap is destroyed.


Rust trap

^ rust trap Rust trap.png
Generates Anywhere
Effect wets items

A rust trap sprays you with water, rusting any rustable items you wear where it hits. Gremlins like to use these traps to multiply. Iron golems will be instantly destroyed by these traps. If you are polymorphed into an iron golem, you will take damage equal to your monster form's maximum HP, killing your monster form and reverting you to your natural form. The half physical damage extrinsic applies.

You can use a rust trap as an infinite, if somewhat slow, source of blanking scrolls and spellbooks and diluting potions, by wielding them, removing any other rustable gear, and repeatedly triggering the trap.

To remove: Dig a pit into the ground while standing on the trap, then fill the pit.

A gush of water hits you on the <body part>!
Your armor in the corresponding slot takes water damage.
A gush of water hits you!
The trap hit your body armor slot, or you are an iron golem.
You are covered with rust!
You are an iron golem and were hit by the trap. Your monster form will be killed unless you have half physical damage.


Sleeping gas trap

^ sleeping gas trap Sleeping gas trap.png
Generates level 2+
Effect Releases sleep gas

A sleeping gas trap puts you to sleep for up to 25 turns, unless you have sleep resistance or are polymorphed into a naturally breathless monster. An amulet of magical breathing does not protect you. Monsters are also subject to the trap's effect.

To remove: Dig a pit into the ground while standing on the trap, then fill the pit.

A cloud of gas puts you to sleep!
You trigger a sleeping gas trap and are put to sleep.
You are enveloped in a cloud of gas!
You trigger a sleeping gas trap but are unaffected.


Spiked pit

^ spiked pit Spiked pit.png
Generates level 5+, Fort Ludios
Effect Prevents movement, damage

These are just pits which do 1–10 damage. Each time you fall in, there is a 16 chance that the spikes will be poisoned, which can be fatal for a character without poison resistance. Metallivores can eat the spikes out of a spiked pit, turning it into a normal pit. The spikes are never poisoned when a monster falls in.[34] The treasury in Fort Ludios contains many spiked pits along with its land mines.

Pets that fall into a pit can be helped out by standing adjacent to the pit and untrapping in the direction of the pit. When you do this with a spiked pit, if you fail to remove your pet, they will suffer the effects of falling onto spikes each time you fail, making them angry (reducing their tameness) and counting as abuse for resurrection from the wand of undead turning. If they die at your hands, you suffer the consequences of killing them in a trap yourself (−15 alignment and an angry god).

To remove: Push a boulder into it.


Squeaky board

^ squeaky board Squeaky board.png
Generates Anywhere
Effect Wakes monsters

A squeaky board wakes nearby sleeping monsters. If a monster steps on a squeaky board on your level, you "hear a distant <note> squeak", or "A board beneath <monster> squeaks <note> loudly" if in sight. (The pitch of the squeak is meaningless, but each trap has only one note associated with it.) For you, "nearby" means within a distance of 20 × XL. (For example, level 5 gives a 10-square radius, level 10 gives 14, and level 15 gives 17.) For monsters, "nearby" means that the distance is less than 40 (a 6-square radius).[36]

The note may be any note of the chromatic scale,[37] and no two boards on the same level will squeak with the same note unless there are at least 13 squeaky boards on the level.[38]

To remove: #untrap, but you must select a potion of oil (which will be consumed) or a charged can of grease (one charge will be consumed).


Statue trap

` statue trap Statue trap.png
Generates level 8+
Effect Statue on its space comes to life

Statue traps look like normal statues of a monster, until you try to walk on the same square as one. When you walk on the trap, it will transform the topmost statue on the trap into the monster it depicts. A statue trap can also be activated by searching, zapping force bolt, or applying a pick-axe. Technically, stone to flesh doesn't activate the trap, it just reanimates the statue if the monster was fleshy, otherwise it turns it in to a meatball. A stethoscope will give a revealing message to healers only, but will not activate the trap. Monsters will never set off these traps.[40]

Because of these traps it is a good idea to far look any statue you see. If the statue is of a monster you would rather not fight, don't step on it. If you have automatic searching, don't even go near it. However, you can throw another statue, preferably one of a weaker monster, onto the trap and then activate it. The new statue will come to life, leaving the old one inanimate. Zapping the trap with a wand of teleportation will teleport the statue without activating it. A wand of polymorph will not set it off either.

Trap statues contain the inventory a monster normally starts with. Unlike ordinary statues, they cannot contain spellbooks.[41]

To remove: Set it off.

Teleportation trap

^ teleportation trap Teleportation trap.png
Generates Anywhere except non-teleport levels
Effect Teleport within the level

This teleports you to a random location on the map, unless it is a vault teleporter located in a closet behind an ad aerarium engraving, in which case you are teleported to the vault. Ad aerarium engravings may also appear in front of closets with level teleporters, which will not put you inside a vault, so it is not wise to blindly walk into a closet without identifying the trap first.

Magic resistance will prevent you from being teleported. ("You feel a wrenching sensation.") If you want to use the teleporter (for instance, to enter a vault), you may use ctrl + t to take the teleporter despite magic resistance. A vault teleporter will give you a warning ("This is a vault teleport, usable once only. Jump in? [yn]") before triggering. If one of the squares in the vault is occupied by a monster or a trap (including the portal to Fort Ludios) or is otherwise unsafe, the vault teleport may fail, in which case the trap will act as an ordinary teleport trap, albeit single-use.[42]

To remove: Dig a pit on the same square and fill it with a boulder. If the trap is located behind an ad aerarium engraving, it will disappear after successfully teleporting the player; monsters cannot use it up.


Trap door

^ trap door Trap door.png
Generates levels with diggable floors, closets, Castle
Effect Fall to lower level

A trap door is identical to the simpler hole except that it starts out hidden. When triggered, you fall to a deeper dungeon level. Just like a hole, 2 or 3 levels is common, there is no upper limit, and you cannot fall beyond the Castle. Monsters never fall more than one floor.[44]

Generation: May be randomly generated at any dungeon level. Trap doors cannot be randomly generated on levels with non-diggable floors such as the vibrating square level or the Castle, although the Castle contains several statically placed trap doors. If the floor is non-diggable, the trap door is replaced with a falling rock trap. Trap doors cannot be generated beneath a boulder. They are sometimes found in closets, with "Vlad was here" engraved in front of the door.

To remove: Push a boulder into it.


Vibrating square

~ vibrating square Vibrating square.png
Generates Unique
Effect None
Main article: Vibrating square

Despite not really being a trap, the vibrating square is internally represented as a trap, and is thus detectable by methods that detect traps, such as a crystal ball. This also prevents teleporting directly onto the vibrating square, so you'll need to pick a square next to it when using controlled teleports to reach it faster.


" web Web.png
Generates level 7+ and with giant spiders
Effect Prevents movement

A spider web is a rare type of non-magical trap. It is the only trap to use the " symbol, rather than the ^ symbol. When triggered, you will be unable to escape it for 0–12 turns, depending on your strength. If your strength was high enough to escape in 0 turns, then "You tear through a web!" and the web is destroyed.

If you are wielding Sting, you always escape in 1 turn ("Sting cuts through the web!"), leaving the web intact.

Acidic monsters dissolve webs they step into, and fire elementals burn them away. Titanotheres, balucitheria, purple worms, jabberwocks, iron golems, balrogs, krakens, and mastodons tear through webs on the same turn they walk into them, destroying the web.

Spiders, amoeboid monsters, and whirly monsters may move into webs without becoming stuck.

If a bugbear or an owlbear gets stuck in a web outside your sight, then you will hear "the roaring of a confused bear".

Attempting to untrap stuck monsters risks trapping you and spreading the web.

You can produce webs with the #monster command if you are a spider. All web-related messages reflect whether things are happening to "your web" or "a spider web".

Generation: Wherever a web trap randomly generates, a giant spider is also generated.[46] Conversely, when a giant spider generates at level-generation time, a web trap will usually be created under it.[47]

To remove: #untrap (difficult), walk in with greater than 18/50 strength, or burn away with a wand of fire. If you fail to #untrap a monster that is in a web, you will become stuck in a second web that is created at your current position. You can fill up the entire dungeon with webs in this way, if you so choose.[48]

Container traps

Main article: Container trap

Containers can be searched with the #untrap command. A high luck can be helpful in avoiding the effects of container traps. Bad luck increases the likelihood of more dangerous traps. Be careful of trapped containers in shops; you will be charged for any items that are destroyed if you set off a trap that damages the merchandise. Container traps include:

Door traps

Trapped doors (and rarely, cursed tins) will explode when opened ("KABOOM!! The door/tin was booby-trapped!"), causing damage, abusing strength and possibly constitution, and stunning you. The damage and duration of the stun depend on a number of factors, including but not limited to your level and how deep you have been in the dungeon.


Avoiding traps in the dungeon takes patience and care. Therefore, the more time-consuming of these methods are only worthwhile when you are especially vulnerable. You can minimize your chances of stepping on a trap by paying close attention to monsters, pets, noises, and terrain. Be wary of the telltale signs of traps such as conspicuous boulders, suspicious corpses, and piles of rocks, darts, or arrows. Traps that you've already discovered will also not be visible under items like these, so it's a good idea to use the trap id command if you need to step onto that square that looks suspicious, even though you may have already been in that area and discovered all traps. By walking only where you have seen pets or monsters safely walk, you can avoid most traps. Remember where you have safely stepped before. Elbereth can cause monsters to flee, possibly uncovering traps as they do. A leashed pet will whine if it is near a trap. Magic resistance and fire resistance can help nullify some of the more dangerous effects of traps.

The search command is a great way to uncover traps without setting them off. #Untrap can be used on doors and containers. You can improve your chances of finding traps if you:

Some items can be useful in detecting traps, although they may have better uses elsewhere:

Because of technical limitations in the level format, only one trap can exist on any given square. If you aren't able to #untrap a physical trap, or if the trap is non-physical, you can usually remove most traps by entering the square and digging a pit. This will overwrite the existing trap in the level data, replacing it with a pit trap. You can then leave the pit and avoid it, or fill it by pushing a boulder in. The downside to this strategy is that you must expose yourself to the trap by entering its space.


The "fake bones" found on early traps are introduced in NetHack 3.6.1.



^ ice trap File:Ice trap.png
Generates Sheol, trap rooms
Effect Deals cold damage, freezes inventory

UnNetHack adds ice traps, which generate in Sheol and are a cold counterpart to fire traps. The amount of damage is the same, but the damage type is cold instead of fire. These traps also have a small chance of appearing in a trap room.

Also in UnNetHack, 10% of rolling boulder traps will also generate an archaeologist corpse, a bullwhip, and a 13 chance of a fedora.


In SLASH'EM, it is possible to disarm a fire trap with a non-cursed potion of water, similar to using a potion of oil on a squeaky board. This will also generate 1–4 potions of oil based on Luck. Since oil can then be diluted back to water, the large number of fire traps in Gehennom offer an effective way of multiplying one's water potions.

Untrapping a rust trap will turn the trap into a fountain if successful. This is also true in dNetHack.

Slash'EM Extended

Slash'EM Extended adds many new types of traps.


In xNetHack, you are asked for confirmation when stepping onto a square with a trap you have already found (and are not clearly immune to). This eliminates the problem of accidentally walking onto traps that you can't see, without needing to use the trap id command at every step.

Door traps can now have a variety of effects, such as waking monsters or wetting items in your inventory. Some changes are made to other traps as well; for instance, webs can be removed by using Shift + F with a bladed weapon. See xNetHack § Trap changes for a full list of these.


In FIQHack, level teleport traps do not disappear when used[49].

Also, remember that lenses in FIQHack provide automatic searching.

Encyclopedia entries

Magic portal

Portals can be Mirrors, Pictures, Standing Stones, Stone
Circles, Windows, and special gates set up for the purpose.
You will travel through them both to distant parts of the
continent and to and from our own world. The precise manner
of their working is a Management secret.

[ The Tough Guide to Fantasyland, by Diana Wynne Jones ]

Squeaky board

A floorboard creaked. Galder had spent many hours tuning them,
always a wise precaution with an ambitious assistant who walked
like a cat.
D flat. That meant he was just to the right of the door.
"Ah, Trymon," he said, without turning, and noted with some
satisfaction the faint indrawing of breath behind him. "Good
of you to come. Shut the door, will you?"

[ The Light Fantastic, by Terry Pratchett ]

Trap door

I knew my Erik too well to feel at all comfortable on jumping
into his house. I knew what he had made of a certain palace at
Mazenderan. From being the most honest building conceivable, he
soon turned it into a house of the very devil, where you could
not utter a word but it was overheard or repeated by an echo.
With his trap-doors the monster was responsible for endless
tragedies of all kinds.

[ The Phantom of the Opera, by Gaston Leroux ]


Oh what a tangled web we weave,
When first we practise to deceive!

[ Marmion, by Sir Walter Scott ]

Fire trap

'Let him be for a while,' said Cohen. 'I reckon the fish
disagreed with him.'
'Don't see why,' said Truckle. 'I pulled him out before it'd
hardly chewed him. And he must've dried out nicely in that
corridor. You know, the one where the flames shot up out of
the floor unexpectedly.'
'I reckon our bard wasn't expecting flames to shoot out of
the floor unexpectedly,' said Cohen.
Truckle shrugged theatrically. '_Well_, if you're not going
to expect unexpected flames, what's the point of going

[ The Last Hero, by Terry Pratchett ]


  1. mktrap in mklev.c
  2. rndtrap in sp_lev.c
  3. src/mklev.c in NetHack 3.6.1, line 1391
  4. src/mklev.c in NetHack 3.6.1, line 1458
  5. trap.c in NetHack 3.4.3, line 2970
  6. trap.c, line 1321 (Anti-magic field trap on you) trap.c, line 2500 (On monsters)
  7. disarm_shooting_trap in trap.c
  8. trap.c, line 636 (Arrow trap on you) and trap.c, line 1825 (On monsters)
  9. trap.c in NetHack 3.6.2, line 1062
  10. hack.c in NetHack 3.6.2, line 1202
  11. trap.c in NetHack 3.6.2, line 2271
  12. disarm_shooting_trap in trap.c
  13. trap.c, line 663 (Dart trap on you) and trap.c, line 1742 (On monsters)
  14. trap.c, line 3532 on you, trap.c, line 1437 on monsters
  15. trap.c, line 3505 (Fire trap on you) and trap.c, line 1403 (On monsters)
  16. teleport.c in NetHack 3.4.3, line 1107
  17. trap.c, line 944 (Hole on you) and trap.c, line 1889 (On monsters)
  18. trap.c, line 692 (Falling rock trap on you) and trap.c, line 1759 (On monsters)
  19. trap.c in NetHack 3.4.3, line 2084
  20. trap.c in NetHack 3.4.3, line 2092
  21. trap.c, line 1111 (Landmine on you) and trap.c, line 2083 (On monsters)
  22. random_teleport_level in teleport.c
  23. trap.c, line 959 (Level teleporter on you) and trap.c, line 1988 (On monsters)
  24. trap.c, line 1178 (Magic portal on you) and trap.c, line 1989 (On monsters)
  25. trap.c, line 1058 (Magic trap on you) and trap.c, line 2076 (On monsters)
  26. trap.c, line 861 (Pit trap on you) and trap.c, line 1940 (On monsters)
  27. trap.c, line 1081 (Polymorph trap on you) and trap.c, line 2121 (On monsters)
  28. mkroll_launch in trap.c Boulder placement for boulder trap
  29. trap.c, line 1165 Player activating a boulder trap
  30. trap.c, line 2131 Monster activating a boulder trap
  31. trap.c, line 1165 (Rolling boulder trap on you) and trap.c, line 2131 (On monsters)
  32. trap.c, line 759 (Rust trap on you) and trap.c, line 1820 (On monsters)
  33. trap.c, line 1226 (Sleeping gas trap on you) and trap.c, line 1807 (On monsters)
  34. trap.c, line 928 (dotrap can call poisoned in mon.c); trap.c, line 1940 (but mintrap cannot.)
  35. trap.c, line 861 (Spiked pit trap on you) and trap.c, line 1940 (On monsters)
  36. wake_nearby in mon.c (for players) and wake_nearto in mon.c (for monsters)
  37. src/trap.c in NetHack 3.6.0, line 1467
  38. src/trap.c in NetHack 3.6.0, line 360
  39. trap.c, line 730 (Squeaky board on you) and trap.c, line 1777 (On monsters)
  40. trap.c, line 1054 (Statue trap on you) and trap.c, line 2073 (On monsters)
  41. Trap.c in NetHack 3.4.3, line 271
  42. src/teleport.c in NetHack 3.6.1, line 384
  43. trap.c, line 955 (Teleportation trap on you) and trap.c, line 1998 (On monsters)
  44. teleport.c in NetHack 3.4.3, line 1107
  45. trap.c, line 944 (Trapdoor on you) and trap.c, line 1965 (On monsters)
  46. mklev.c in NetHack 3.4.3, line 1266
  47. mklev.c in NetHack 3.4.3, line 763
  48. trap.c, line 964 (Web on you) and trap.c, line 2002 (On monsters)

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It may contain text specific to NetHack 3.4.3. Information on this page may be out of date.

Editors: After reviewing this page and making necessary edits, please change the {{nethack-343}} tag to the current version's tag or {{noversion}} as appropriate.