Trap Examples
Trap Examples

Trap Examples


Trap Examples

So far we have discussed many of the problems with traps and looked at the steps to building a trap that can become an encounter that the players and characters can interact with in the game. This article is going to walk through the steps of creating a trap to give you an example of how it works.

I am going to start by looking at a poorly designed trap from one of D&D’s published adventures and modify it into a more fair and more interactive trap that the players will feel good about solving.

The setting for this trap is a lost temple deep underground. Near the back of this temple there are four hallways that have one pit trap in each hallway. At the bottom of the pit is a particularly deadly form of ooze which would likely kill anyone who fell in (depending on their level when they go here). The trap, as written, gives basically no interaction with the players before they fall in. It relies completely on a perception check, upon which a success renders the trap useless. If the trap is triggered, the only interaction is a dexterity saving throw to avoid falling in. That’s it. The only interaction is a dexterity saving throw and even if the player passes it, they just feel lucky.

Instead of running through the entire set of questions for this trap, I’m going to just look at the negatives of the trap and how to fix them:
1) There is not a lot of interaction with the trap once spotted.
2) There is nothing for the players to feel good about solving.
3) Finding the trap is based on only one die roll ( a perception check)
4) There are no clues or difficulty progression.


First, I want to make sure there are starting clues for this trap. One option would be to describe the cracks or shifted tiles near and around the pits, but then the trap will likely be too easy, and there still isn’t much for the players to solve due to this trap not having multiple parts. I’m going to solve this by using increasing difficulty. In addition to the four traps in the hallways, I’m going to add similar traps earlier in the temple to allow the players to gather clues. Players recognizing the pattern and series of clues will create interaction and if the players manage to solve it, they will feel good about that.

Now I have to decide on the clues for the traps and the skills the party can likely use to solve it. Now that I am setting up several traps in a row, I also need to think about the design and story a little more instead of just having holes in the floor. Here’s what I came up with: This temple had many worshipers to the god of pain. Their temple had several pit traps along it’s hallways, along with a button to activate each one. Every trap has a carved stone face of the god of pain within five feet of it. Hidden on the face is a button that triggers the nearby tile to swing loose into the pit. However, since the ruined temple is hundreds of years old, the mechanism that triggers the tile has been broken, and the tiles, without the support of a floor under them, have become too weak to stand on and some have broken loose.

The trapped part of the temple will look like this. With traps in three separate areas.

pit traps


The first trap they encounter will be completely open due to a collapsed portion of the wall nearby.
Given clues:
-5×5 hole,
-lots of rubble at the bottom
-smooth sides in the pit

Skill checks:
Perception- sees metal rod in exposed wall
Perception- sees parts of a face in the stone at the bottom of the pit
Investigation – (on rod) metal hook under the tile (when button was pressed it dropped it)
Investigation- (on pit) smooth walls look like they were carved out and man made. The tile collapsed into the pit.
Religion- (on face) recognizes the stone face as the god of pain
History- God of pain is known for sacrifices, torture devices, and trapsfirst trap

This series of clues notifies players this area might be trapped, gives them history and interesting information about the area, and notifies them of the type of traps as well, allowing for clever solutions like hitting the floor in front of them with a stick to check for hollow floors.

Second pit trap:
The second trap is partially collapsed. The tile is still locked in place, but about a foot of it is cracked and has fallen in. Nearby is a stone face carved into the wall, the same face as the previous trap if they managed to spot it.

Skill checks:
Perception- Sees goo near the hole in the tile
Perception- Sees something reflecting light below (ooze)
Investigation- finds button inside the mouth. (can press it to drop the tile into the pit and release the ooze.second pit trap

Now that we have set them up with possible clues, some they might have and some they might have missed, they come to the actual trap, the one we want them to solve.

Clues: The only clues we are giving up front is the stone faces on the wall.

Here they don’t get many clues. They have to use the previous traps to anticipate what is here. They can choose to rely on a difficult general perception check, or if they know what they are looking for they can combine information or use more specific methods to search for this trap.


This time, when the players solve the trap by recognizing that the lady of pain’s face is carved above the last two traps, or they thump ahead of them to listen for hollow floors, the players will have a sense of accomplishment. They had to do something to recognize a pattern. In addition, if the players do blunder into the trap, they will often recognize the clues after and feel silly for not seeing them instead of feeling unlucky or targeted by the DM.


Second trap… Designed from scratch

Designing the story

This trap will be for a ruined temple in a jungle inhabited by Yuan-ti (a race of snake people). Snakes made me immediately think of a poison trap that the Yuan-ti spend time extracting from pet snakes.


Designing mechanics

Trigger will be a pressure plate on the floor hidden by the stone tiles that line the floor. The pressure plate pushes on a set of gears under the floor that turn to open five holes on the far wall. Each hole has behind it a glass container which gets crushed by the rotating gears releasing its stored poison into the room. The poison evaporates instantly and fills the room within three seconds. The 200 lb. stone pressure plate is set into the floor and cannot be jammed or held up without strong magic.


Obvious solutions

Now that I know how it works, the most likely way for the party to avoid this trap is to walk around it, but I want there to be more. The holes in the back wall are not perfectly rounded and are rough, making them hard to plug up without having something malleable. Driving a spike into the hole, for example, would not plug it and would shatter the glass jar behind it triggering the trap. The trap has been triggered many times before. Each time it is reset the wall is reopened and the hole patched with a hardened mud mixture that can be torn away fairly easily. This will allow access to the jars (which can be used as poison grenades) and will disarm the trap. Because I am making the pressure plate very difficult to disable, I will have a small hole in the wall on the side which will give access to some of the gears embedded within the wall. This gives two clear ways to disarm the trap if they don’t go around it.


Trap interactions

The Yuan-ti are immune to the poison, however they do not want to trigger the trap and waste resources. This means they need a bypass for each trap. This trap will be in a room that has a large central column. The column divides the room in two, the left side having the pressure plate that covers most of the floor and the right being normal stone floor. The Yuan-ti go to the right to get around the trap. They also have extra glass jars which contain more poison to reload the trap once triggered. Once the trap goes off the glass falls to the ground and the wall has to be pulled open again to insert new ones.

Picking clues

First a description of the room will be given with this map and description. Inserted into the description will be three main clues for this trap. The entire room and any adjacent rooms will have a strong acrid smell that burns the character’s noses as they enter. There will also be a layer of dust on the floor which show signs of the Yuan-ti’s tracks. I also know that there is no way any character will find that hole in the wall unless I give them reason to. Air flowing through the chamber and between the walls blows over the hole causing a faint whistling sound from the left side of the room. Now the hole has a chance of getting investigated.


Choosing skill checks

  • Survival
    • Tracks in dust all lead to the right
  • Perception
    • Dust is actually more of a film (from the gas settling)
    • From the far side of the pressure plate, broken glass can be perceived. (does not require check from up close)
    • Rat bones discovered near corner of room
  • Nature
    • Identifying film as residue not dust
    • Nature check on the bones in a corner near the entrance of the room shows they were rats
  • Investigation
    • Slightly depressed tiles over pressure plate
    • Sound near wall is coming from a hole, inside are gears
    • Pressure plate estimated to weigh a few hundred pounds, too heavy to move.
  • Medicine
    • Can determine rat bones have strange black vein like markings under their surface. Might be poison.
  • History
    • These Yuan-ti are known to be particularly deadly, using poisoned arrows. They have lived in this ruined temple for over 300 years
  • Sleight of hand
    • Jam the gears through the wall
    • To break the wall without breaking glass jars
  • Acrobatics
    • A small creature weighing less than 100 lb. can make an acrobatics check to move across the pressure plate without triggering it
    • If a creature skirts the wall they can make a check to not step on the pressure plate

Traps example

Increase difficulty

This trap will likely be pretty easy for the characters to avoid once they know it is there. I’ve given three clues to help them discover the trap, two of which (the smell and the tracks) should lead them to believe there is danger. To increase the difficulty of this trap I might put the small hole to the gears directly over the pressure plate. If they don’t heed the warnings and just walk forward to look at the sound then they have a chance of setting it off. But my goal with this trap is not really to get them to hit this first trap, rather it is to set them up for interactions more difficult traps in the future.

Several rooms later the party will come across another poison trap. This time, the pressure plate will cover from wall to wall making it much harder to avoid. An acrobatics check will be required to skirt the edge. But the Yuan-ti need a way to cross as well, so I will have a secret door they can pass through in snake form. The party will be given clues about the door as well by looking for where the tracks lead or just searching the room for several minutes. However I will not tell them about the tracks in this room because farther in the trap gets triggered less and the film is less visible (I want it to be harder for them). The acrid smell will still be their one clear clue.

I will have a third poison gas trap near the end of the ruins. This trap will be made much harder by removing several of the solutions (only if they are a higher level party). The trap will be placed at the bottom of a 30 foot ladder in the dark. The pressure plate will be directly below the ladder making it difficult to get down. The acrid smell wafting up will be the parties only initial clue for this one. They will have to attempt to solve the trap from a distance, without a good look at it. The Yuan-ti go through a smaller hole in the wall that leads down to avoid this trap, but it is too small for medium sized characters to fit through. Either some acrobatics/athletics checks will be required to jump from the ladder over the trap, it can be triggered and waited out, magic can be used, or they are just going to have to hold their breaths and take the damage.


Running the Trap


Giving Clues

Each of these traps will have the acrid smell as the main indicator of their proximity. The first trap will have several clues woven into the description of the room setting up that the characters should be cautious and investigating closely. Once the first trap is identified, it will help them spot the next two which are much harder to solve. If the first trap isn’t noticed at all, then I may add one more hint to the second.

I will also have conditional extra clues to give. For example if the party is carrying a light source like a torch, I will give them the clue about a glint of light on the far side of the room (the glass reflecting the light). If they have a dwarf in the party I will also tell them that he notices a slight dip in the stone floor to the left and a difference in texture on the back wall.

Creating interaction

The Yuan-ti, being immune to poison, can use the trap as a weapon against players by triggering it themselves. If any Yuan-ti escape a fight, they can come back and try to do this later while the party is in the room. If they get in a fight, setting off the trap can also be a great tactical advantage for the Yuan-ti to block an escape path or force them to flee or take damage. The solving of some of these traps will be fun as well and if the party tries to disable them, they run the risk of accidentally triggering them. The reward of poison grenades might be worth the risk though. A glass jar in a backpack could also be a liability. If someone carrying one takes a crit or falls more than ten feet, perhaps the jar has a chance of shattering.


Adjust difficulty

If the party misses the entire first room I would make sure to increase the clues for the second trap. If the players I’m with are not the intellectual type and just run into the first trap, I might also add some help for them at the second. Lastly, I will make sure that my players know that the traps are puzzles for them to solve. They, as players, have to use  the clues I give them to solve the trap. Players often become used to the way poorly designed traps work: they do one roll and either find and avoid or miss and trigger. In my sessions, I let new players know that finding it just tells them where it is. There is lots more interaction to be had and sometimes I’ll even hint that investigating this trap could lead to foreshadowing about others. I have to train my players how I DM.


I have a rule for myself that a quality trap is one that can kill a PC and the players will not be angry about it. Before I put any trap into the game, I ask myself, if this trap happens to kill a PC, would everyone be okay with that? It’s pretty rare that a trap gets the killing blow on someone, but when you fallow these steps, you can make a trap that does just that. I’m going to attempt to make an insta-kill trap that still feels fair to the players and fun to interact with. This will be tough.

Designing a Fair Insta-Kill Trap

Designing story

The boss in his setting is a very powerful wizard. So lets go back to an original D&D insta-kill trap, the sphere of annihilation (A magic floating orb that instantly disintegrates anything it touches). The wizard built this trap for two purposes: to prevent entrance into his main lair and to put unwanted things into (prisoners, incriminating documents, and anything else he wants to destroy). The creation of a sphere of annihilation is extremely difficult so in this case there will be only one throughout the whole dungeon. The wizard bypasses the sphere by carrying a ward-stone that allows him to walk through the trap trigger without setting it off. There is only one ward-stone and he carries it with him at all times.


Designing mechanics

The sphere is set into a patterned pentagonal hole in the wall. The sphere creates a void of darkness and destroys everything that touches it, making it very difficult to investigate because characters see only darkness when they get close and look at it. The sphere will be set into the wall of a room. On the opposite side of the room, lined up with the sphere, is a long hallway that leads into the boss’s lair. The trap kills anyone who enters the blackness instantly. If a character puts their arm in, it’s gone. But the trap also has two triggers. If anyone touches or enters it, it shoots forward and down the hall.

The second trigger is in the hallway itself. About 20 feet in is a magic ward that will trigger the sphere to shoot down the hall if anyone not carrying the ward-stone passes through it. Once triggered, the sphere of annihilation shoots out of the hole in the wall and flies down the hallway disintegrating everything in it’s path. In the wizard’s lair is another pentagonal hole in the wall which will catch and return the sphere to its original spot, resetting the trap. Creatures in the hallway have a high chance of getting disintegrated if the trap fires while they are in the hallway.  Even if they get out of the way, they have to deal with the sphere coming back. The trap is not particularly well hidden beyond that most people don’t know what the blackness does. The ward in the hallway is a series of runes inscribed all the way around the floor, walls, and ceiling. They are visible to any character walking through the hallway as a faint white glow.


Obvious solutions

Triggering the trap by putting a stick or something in it and then trying to time their run through the hallway is one possible solution. However I think the wizard is smart enough to deal with this. The “touch” trigger only goes off when the sphere has consumed a certain amount of biological tissue. So sticking a stick in it will disintegrate whatever part touches it but not send the sphere flying. However sticking an arm into the sphere will not only lose you a limb, it will send the sphere flying at you as well. To trigger it safely the party would have to throw a creature into it… if they are evil or desperate.

The next solution would be to try to outrun it. I get to set the speed of the sphere and I would like to make outrunning it a possibility, but a very difficult one. So I will say that once in the hall, outrunning it requires a movement speed of 45+ to automatically succeed (go monks!), a speed of 40 will be possible, and for a speed of 35 or less it will catch up.

Players will surely ask if there is any way to dodge or duck under it while in the hallway. I want this to be hard so I am going to say no, with one exception. Two thirds of the way down the hallway will be a missing stone in the ceiling/wall. It is just enough space for one small character to squeeze into given proper strength to brace themselves up there.


Picking clues

Since this trap is so deadly, I must make it very clear. Here is a problem I must avoid because it will piss off all the players.

DM: you see a void of blackness set into the wall.

Player: Ok I investigate and roll a bunch of checks to see if I can figure it out.

DM: nope, it’s just blackness, you can’t see into it. All you know is it’s magic.

Player: (in their head) well, it seems to be like a teleportation thing, so I’ll go in it since it’s clearly where the DM wants us to go and I want to help him by following the adventure instead of going off script.

Player: I go in

DM: you are dead

Sometimes the players make decisions based on the fact they are playing a game or wanting to help the DM. For example when the DM says, “you see the massive entrance to the dragon’s cave”, the players would be jerks if they said, “yeah that’s too scary, lets go back to town”. They know the DM set this up for them and they accept that putting themselves in danger is part of the fun, even if it is not the best choice for their characters health and wellness. If I kill them for trying to help me, they have every right to be upset.

So my starting clues for this trap must be well thought out. First, it must be clear this is a trap and not a portal. This dungeon will have several other traps in it and I will have several of them shoot out of smaller pentagonal insets, similar to this one. This pattern will give them a clue that it’s a trap.

The second clue will be the room they are in. It will have several prison cells as well as some torture devices. A set of chains with cuffs that hook to the legs will be set 10 feet directly in front of the sphere. The wizard straps prisoners in and sets off the trap to kill them. It disintegrates every part of their bodies except their feet and ankles left bound to the floor, which it travels over.

Third will be a hot searing pain whenever they move within a few inches of the sphere. This will likely prevent them from touching or jumping into it of their own will.

Fourth will be the burnt walls all the way down the hallway. The sphere is almost exactly the same size as the hallway to make sure no one can just duck it. It is only a few inches off the floor but it touches the walls as it travels, leaving disintegrated stone marks down the hall.

The fifth clue will be the ward, which will be visible as a ring of white light to anyone in the party when they are in the hallway. Any investigation reveals each mark as arcane writing.

My last clue will be the journal of the wizard himself and/or a log of prisoners. Finding either of these show that he use the device to threaten or kill prisoners he captures.  

I think that feels fair. There are plenty of warnings and no red herrings to make the party believe they should be jumping into this blackness.

Sphere of annihilation

Choosing skill checks

  • Acrobatics
    • To hold themselves up in the small nook in the ceiling where the stone is missing (only one character can do this and they must be small)
    • If the trap does get triggered from close range, an acrobatics check to dive out of the way or a dex save could be used to only get an arm or a leg burned off instead of dying outright.
  • Arcana
    • Arcana check can be used on the sphere itself to determine that it is immensely powerful and has destructive properties.
    • Arcana check will also give clear indication it is not a teleportation device
    • The source of the burning when within a few inches is magical
    • The scorch marks on the wall were created with some sort of magic and are not natural burn marks
    • The ward symbols can be deciphered as some sort of trigger or alarm
    • Can figure out that passing through the ward will trigger it, even if invisible or ethereal
    • A high roll will reveal the connection between the ward and the sphere
  • Athletics
    • To outrun the sphere (only if you have a speed of 40 or 45) (50+ can outrun without a roll)
    • For a character to hold themselves up in the missing stone hole in the ceiling of the hallway (either athletics or acrobatics can be used)
  • History
    • This wizard practiced very destructive magic and was kicked out of the mage’s guild
    • The pentagonal symbol and design on the wall is an ancient sign of destruction
  • Investigation
    • The hole the sphere is in is completely back and has no apparent triggers or mechanical workings
    • Looking at the wall can make it more clear that the something shoots from the hole and down the hall.
    • The chains and cuffs on the ground have blood, torn skin, and hair around them from people struggling to get out.
    • A tiny piece of bone can be found near the cuffs
    • investigating the ward shows only that it is arcane and that the ward itself does not explode or cause damage.
  • Medicine
    • Medicine check on the chains and cuffs shows that people were tearing chunks of skin off while in them, presumably trying to escape
    • The tiny chunk of bone is cut perfectly smooth, with the cut part singed and blackened
  • Nature
    • None of this is natural, it’s all arcane
  • Perception
    • To judge the distance of hallway and know they likely couldn’t outrun
    • To see the catching device on the far wall from anywhere behind the ward. (closer reveals it automatically)
    • Judging by the perfectly smoothed burn marks in stone, the trap cannot be blocked.
  • Religion
    • The symbols on the ward are arcane not religious
    • The pentagonal inset is a religious symbol meaning “annihilation” from a specific religion (pick to match campaign)
  • Stealth
    • Only used to get into the room quietly if they don’t trigger the trap


I don’t need to make this trap any harder so I will skip that part. However, I want to take a second to make sure that there still are ways to solve it without being too hard. The characters are high level and have access to magic and skills that will help them. They can attempt to teleport past the ward with a number of high level spells. They can also use the same spells to teleport/dodge the sphere as it comes at them. Monks, barbarians, halflings, and gnomes, have an escape by either being fast enough to outrun it or to try jumping into the tiny hole in the ceiling/wall. If they encounter the wizard outside his room they can also take his ward and use it to bypass the trigger.

The sphere itself will ignore most magical effects, such as reverse gravity won’t make it fly up and it is far too powerful for a dispel magic. However, if some form of teleportation portal is open in front of it, or a teleportation circle is activated under it, will continue moving straight and come out of wherever the teleportation leads…. This means that it will continue moving forever in that straight line. That could be fun.
I am satisfied that the party will have enough clues to be warned of this trap and to solve the puzzle.

I’m not going to type up the Running Traps portion of this trap because that is usually done in game depending on how things play out. I can imagine having the wizard capture a character and shackling them in front of the trap or having an NPC in the prison room when the party enters. Hopefully you liked this trap and can use it in your high level games. If anyone uses it, or has ever used a sphere of annihilation trap tell me the story or if your players were pissed about it in the comments below.


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