Creating interesting traps

Traps are a genre staple. Here are some principles for creating interesting traps.

Traps are usually present to guard something specific. The presence of a trap will tell the players that there is something worthwhile to be gained by braving the trap. Gambling risk and reward is an interesting choice for the players.

Create meaningful exploration by telegraphing the presence of traps and having the players figure out how to safely get past them. It’s boring if a trap triggers while an adventurer walks down a hall, deals a Wound, and the adventurer says “OK. I keep going, I guess.” Traps, like the rest of the game, should involve interesting decisions.

Telegraph the traps by engaging all five senses. Clues that a trap exists can be found in discolorations of stone, strong smells, grinding gears in walls, temperature differences in the air, etc. If the players follow up on these clues, the traps should be obvious. The essential puzzle is how to overcome the trap, not whether or not a trap exists.

As players investigate traps, speak generously and tell them everything their adventurers can see and understand. Traps should be fun for the entire guild. There are no talents that determine who can pick locks or disable devices. Anybody can interact with traps with the right equipment.

Arbitrate the players’ actions fairly. Good ideas, preparation, and lateral thinking obviate tests of fate. When players start testing fate, they’ve already failed to deal with the trap in a safe way.

Put some of these traps in your dungeon. Use them as inspiration for your own.

1. Mysterious tower, acid lake

There is a tumbledown tower in the middle of an island. The island is in the middle of a bright-green acid lake. The lake is death for whoever falls into it.

Why this trap doesn’t suck: The possible rewards are tantalizing. (A mysterious tower? What’s in it?) The dangers are obvious. (The lake is bright green! Acid is deadly!) This is an open-ended problem with many possible solutions but no one obvious solution.

How to run it: Living creatures who fall into the waters are killed. Unless the player is as direct as saying, “I run and jump in the lake!,” let them test fate to avoid this.

Players should be able to easily experiment to determine how caustic the waters actually are. An item will quickly be Destroyed if placed in the acid lake unless it is indestructible. Carefully touching an item to the surface of the acidic water will simply Notch it.

Spells might help the guild cross the lake. Gust of Wind would allow one adventurer to cross the lake (more if more Resolve is spent). Defy Depths would probably work, but the adventurer’s boots would burn off their feet as they walked on the surface.

Clever guilds might employ the use of flying monsters elsewhere in the dungeon to help them cross the acidic lake.

Anything that’s not (sidebar)

nailed down (sidebar)

There’s a huge number of resources in the role-playing hobby to draw on. RPGs have been around a long time and it’s never been better. There’s a vibrant DIY community of incredibly talented people creating all sorts of blog posts, zines, and indie games. When you set out to create your Underworld, you’ll have an enormous amount of things to borrow from and be inspired by.

Buy some stuff from your favorite creators, slap them together, cut and paste sections from one onto the other, and turn your players loose. Perhaps the first level of your Underworld is the Tomb of the Serpent Kings (Skerples, Coin and Scrolls [blog], 2017), but the deeper levels are sections of Undermountain ( The Ruins of Undermountain , TSR, 1994).

Want to play His Majesty the Worm, but use the optional hex crawl procedures (p. 142) instead of focusing on megadungeon play? Dolmenwood (Gavin Norman, Necrotic Gnome, 2023) can dominate the northwest corner of your campaign map. The Misty Isles of the Eld (Chuck Kutalik, Hydra Cooperative, 2016) and Hot Springs Island ( The Dark of Hot Springs Island, Swordfish Islands, 2017) can be just off the coast of the City.

2. Arrow trap

A hallway has a 10’ stretch of wall, dotted with small holes on either side. The floor contains a pressure plate. Stepping on the pressure plate causes arrows to fire from the holes.

Why this trap doesn’t suck: Pressure plates and traps (arrows, pits, jets of flame, etc.) are genre staples. That’s cool. However, they tend to be both hidden and deadly. That’s a bad combination during play.

You can make these traps not suck by broadcasting the danger clearly and providing a part of the trap for the players to interact with. In this circumstance, the holes are both obvious and interactable. Apply this principle to other types of traps to make tropey traps more fun.

How to run it: If an adventurer steps onto the pressure plate, tell the player they hear a click. They have a split second of real-life time to tell you what they want to do. If they make a move away from the holes—dropping to the floor, launching themselves backwards—they can test Pentacles to avoid the volley. On a failure—or if they do nothing—they take a Wound.

The arrows will only fire once. (They need to be reset after they’re triggered.) If one adventurer triggers the trap, the rest can pass.

The holes on the wall should be a clear indication of danger. Adventurers can trigger the trap prematurely by throwing something heavy onto the pressure plate. They can also leap over it with a successful test of Pentacles. They might plug the holes up with alchemical glue bombs. Let ideas that make sense automatically work.

3. Quicksand

A swampy section of ground is actually quicksand. It begins to inexorably swallow anybody who steps into it— just like the old movies.

Why this trap doesn’t suck: Tropes are instantly understood at the table. Quicksand is a good trope because it’s hidden without being deadly. It traps one adventurer and gives the rest of the guild something to do.

How to run it: If the guild is not moving carefully, the first adventurer in the marching order blunders into the quicksand and gets stuck. Unless they have a tool in their hand or on their belt that could help them with the situation (e.g., rope to lasso over a nearby tree limb), they can’t do anything by themselves to get unstuck. Other members of the guild can test Swords to pull the stuck adventurer out: rope grants favor to this test.

4. Electrified chest

A metal chest on a plinth. The plinth is electrified. The whole room smells of ozone. Nearing the plinth causes your arm hair to stand on end. Touching either the plinth or chest delivers a nasty shock.

Why this trap doesn’t suck: Although the danger of the chest and plinth might not be obvious by sight, the smells and sensations broadcast the danger. Having obvious treasure allows the guild to be instantly rewarded for their cleverness.

How to run it: Touching the chest or the plinth deals Piercing damage.

There are lots of different ways to disarm the trap. For example, an adventurer can knock the chest off the plinth with the butt of a spear to disconnect it from the electric current (though this might break the contents). Dwimmercraft might also open the chest at a distance.

5. Big rolling boulder

A sarcophagus. Behind it, a large devil statue—in a pose like a bowler about to make a throw—holds a massive boulder. Runes on the lid of the sarcophagus promise death for whoever disturbs the rest of Jarl Ninebones.

If the sarcophagus is opened, the statue throws the boulder, which rolls towards the guild Indiana Jones-style.

Why this trap doesn’t suck: It should be obvious based on the statue’s pose what will happen if the guild disturbs the sarcophagus. This gives the guild a chance to plan their approach, get out of the way, or disable the trap before it goes off.

How to run it: Once activated, the boulder will roll past the sarcophagus and chase the adventurers back the way they came. Each adventurer in the boulder’s path tests Pentacles. On a success, the adventurer jumps through the narrow door at the end of the passage, escaping the boulder. On a failure, they take Critical damage.

Players who have ideas such as “Jump in the sarcophagus” automatically avoid the boulder without having to test fate. Players who have ideas such as “Raise a stone wall by casting Wall of Elements with 3 Resolve to block the boulder” disable the trap entirely.

6. Invisible path

A door opens onto a chasm, apparently dropping into an endless pit. Falling into the pit would be certain death. On the other side of the chasm is another door.

In actuality, an invisible bridge spans the two doors, though it does not go in a straight line. Rather, it meanders across the gap.

Why this trap doesn’t suck: The danger is obvious and the solution isn’t. If the guild doesn’t understand there’s an invisible bridge, they can simply leave.

How to run it: The presence of the invisible bridge can be found by reaching out and touching the empty air directly in front of the door. Adventurers can tap on it with a ten-foot pole or tentatively put their weight on the empty air while their companions hold a rope tied around their waist.

The invisible bridge can be painted with paint, spilled ink, smashed lightning bugs, whatever. Sling stones or coins can also be placed to mark the path. Sorcerers can also use Dwimmercraft to activate their second sight and perceive the invisible bridge.

If the players have a good idea on how to ascertain the bridge’s position, they can make their way across.

7. Hungry door

A door frame is filled with a huge, gross, animate, slavering mouth. The teeth grind together, it smiles, it lolls its tongue, it belches. “Feed me!” it barks.

The door will open if it is well fed. It will be sated if it eats five rations or one sizable living creature.

Why this trap doesn’t suck: Like the invisible path, the guild can simply leave the door if they don’t have a good idea on how to get past it. Its danger is avoidable.

Also, the door is gross. Gross things are fun in dungeons.

How to run it: The hungry door, despite being animate, can sustain damage like a metal door. If the guild attempts to smash the door down with something smaller than a battering ram, the door will chew on it and spit it out. This Notches items and/or Wounds the limbs of adventurers.

Feeding the door either requires some resource attrition (feeding it some of their precious rations) or cleverness on the guild’s part. Are they willing to sacrifice one of their animal companions? Can the guild bring the door a captured monster to eat?

8. Flooding fish statue

A shallow pool hosts a large fish statue with a large blue sapphire in its mouth. Removing the gem causes the doors to slam shut and water to gush from the fish’s mouth. Within moments, the room is completely flooded.

Why this trap doesn’t suck: A too-obvious reward should make players suspicious that there is a hidden risk. If the guild makes an effort to position themselves for success before looting the gem from the fish statue, they’ll significantly reduce the risk of this trap.

How to run it: Tell the players that they have the length of three actions in total to try and disable the trap.

The simplest solution is just to put the gem back in the fish’s mouth. This effectively blocks the water. The guild can also try something less valuable of equivalent size.

If the guild has a tool like a crowbar, they can test Swords to smash their way out of the room. On a failure, they’ve wasted one of their actions and the water continues to rise.

A spell like Portable Hole will create a hole large enough for the water to flow out. After a few minutes, the water in the reservoir under the fish statue will run out.

If the guild cannot find a way to stop the flow of water after three actions, it’s okay to let them drown. Adventuring is nasty business.

9. Pyrotechnic mushrooms

The far side of the hallway is cluttered with ugly orange mushrooms growing on the walls, floors, and ceiling. All naked flame in the hallway hisses and sputters. A sulphureous smell pervades the area. If the mushrooms are disturbed, they fill the air with a highly-flammable gas.

Why this trap doesn’t suck: The mushrooms are obviously bad news. The interaction with the guild’s light and the smell broadcasts the danger. Also, interacting with mushrooms will feel different from interacting with mechanical traps.

How to run it: Make it clear the guild cannot pass the mushrooms without disturbing them. If the adventurers have active flames while walking through the area, an explosion is triggered. Anybody carrying a light catches on fire. They take a Wound and one flammable item in their belt/pack is Notched every time an action is taken until they can put themselves out. Everybody adjacent in the marching order also takes a Wound. The adventurers can put their lights out to traverse the hallway—but how will they deal with what’s beyond in the dark?