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DM Advice: Make traps visible [Traps: Part I]

Updated: Aug 1

Typically, traps in Dungeons and Dragons 5e are hidden or camouflaged and have a Difficulty Class (DC) to spot with a Wisdom (Perception) check. It is standard practice to check doors, chests, and dungeon hallways for traps. Frequently. Yet, it's not particularly fun or interesting for the resident Rogue to repeat "I check for traps" every few steps and at every new doorway. That's where 5th edition's Passive Perception comes into play. The Dungeon Master (DM) compares the leader's Passive Perception to the DC of the hidden trap and determines if the character spots the trap. The problem here is that an active Perception check may yield a higher result and tip the party off to a trap they wouldn't have passively noticed. This has left me wondering when to rely on Passive Perception versus making active checks? Should the party frequently have to prompt the DM with "do I see any traps?" to make an active roll?

In my experience, hidden traps end up being not fun and slow the session down. My party has great Passive Perception, so just about any trap is going to be noticed to some degree. Trying to hide a trap from the party or trick them about it ends up being unsatisfying. Traps that are hidden and triggered unwittingly act as a "Hah, gotcha!" moment for the Dungeon Master. It's a power play of sorts. Being a DM means we see all and know all. Our version of the world is "canon," so to speak. The party is at the mercy of this omnipotent entity and they rely on information conveyed to them to make decisions and interact with the world. There must be trust between the party and DM, with clarity of information, for this contract to work.

Hidden traps, in their simplest form as resource thieves, add strain to the relationship between party and DM. That's because of the way a Dungeon Master reveals or fails to reveal information can be self-serving. Let's say the party checks for traps at the entrance of the dungeon, rolls well, and finds none. Great. They take forty steps inside and come to a fork in the tunnels. The party takes the right tunnel and continues, immediately stepping on a trapped tile and getting shanked by wall spikes. They didn't check for traps there specifically and the DC was just above the highest Passive Perception. Are we having fun, yet?

The solution is to make traps visible. I've found it is more engaging and satisfying to have traps be visible from the get-go. The challenge is in avoiding or overcoming the trap while using as few resources as possible. Effectively, traps become Dungeon Hazards and act as puzzles for the party to solve. There's a caveat to this that I will get to later.

Let's discuss traditional traps. For a simple example, the Falling Net trap has a DC 10 to detect. Of course, the party detects the tripwire that triggers it. The solutions to avoiding this trap are simple: step over it, disarm it, or trigger it from a safe distance. A more painful example is a Poison Dart trap. Rules as written (RAW), it requires a DC 15 Wisdom (Perception) check to spot. The party passively notices holes in the wall, spent darts littering the ground, and a dead body 30 paces ahead. An active Perception check, or careful searching, reveals the location of the pressure plate. The solutions to this trap are: step over the pressure plate, disarm it, clog the holes the darts come from, or trigger it from a safe distance. The caster uses Mage Hand to move a couple of items onto the pressure plate, reaching the 20lb limit, and triggers it while the party stands back.

Similarly, a party notices any variety of pit trap. For a Simple Pit, they see a suspicious swathe of ground littered with dirt and leaves, showing minimal signs of foot traffic. Now they have to determine what exactly it is and how to get past it, using resources they have available. Maybe that grappling hook will get a moment to shine, or a 10ft pole will come in handy to poke at debris concealing the pit beneath it. Or they walk around it. Yay.

These are standard fare for traps. Alone, they're not particularly interesting or challenging. When used in tandem with an additional element, the DM and party can create a much more satisfying experience.

Keep in mind that just because the party sees a trap doesn't mean they know what it will do or what the solution is. For example, take a look at the Fire-Breathing Statue. The party observes four dragon statues, two on each side of the hallway. The Dungeon Master describes scorch marks on the stone walls and a charred pile of bones. This is an ideal opportunity for the party to actively check for traps. A DC 15 Wisdom (Perception) check determines the location of the pressure plate. A DC 15 Intelligence (Investigation) check reveals that the statues have a mechanism in their mouths that spew fire and that a pressure plate triggers it. Now they must deactivate it, avoid it, or use it to their advantage against a group of approaching enemies. What if they don't pass the DC 15 check? The investigator accidentally steps on the pressure plate or sets off the mechanism while poking around and triggers the trap.

All of these traps have cues and hints that let the players know loud and clear THERE IS A TRAP HERE. The trap may be "hidden" in a narrative sense, but the DM isn't trying to hide its very existence from the party. It may not always be obvious what the trap does, what triggers it, or where the triggering mechanism is. The important part is that the party is aware of the trap and can decide how they want to overcome it. This creates meaningful interaction, discussion at the table, and allows utility items and spells a chance to be used.

All of the above comes with a big caveat of if the party is moving at a cautious pace and not being chased at high speed through a trap-laden tunnel. Here are some scenarios that may cause the party to bumble into traps accidentally:

  • The room is flooding, on fire, or closing in on the party

  • Enemies are chasing the party

  • The party is actively fighting enemies

  • Reduced visibility or blindness

  • Some other distracting event is taking place

  • Panic and mayhem

The essence of make traps visible isn't simply to make ordinary traps more noticeable. Rather, reconsider what makes a trap interesting and present interactive traps to your players. Look to Dungeon Hazards and complex traps to identify ways of utilizing your party's abilities. For example, the humble Brown Mold is arguably more interesting to encounter than four poison darts shooting out of the wall. Brown Mold grows in patches on the ground and walls, visibly present but seemingly innocuous until approached by a person or heat source. It sucks the warmth from whoever comes near, dealing 22 (4d10) cold damage. If a heat source is nearby it feeds on that warmth and spreads, covering more ground. It's immune to fire damage and destroyed by cold damage. The party is made aware of it by a simple description from the DM as they enter the area. They can choose to avoid it, investigate it, or try to destroy it with fire under the assumption fire would be effective. Or maybe it sounds like descriptive fluff to them and they walk all over it!

A chasm with an icy river below, a pool of lava, a tunnel full of thick webs, and quicksand pit are all "traps" in their own right. Typically described as Dungeon Hazards, these can be used effectively as traps the party must overcome. Remember that traps and hazards don't exist in a vacuum. Alone, they are little more than a nuisance to skirt around. Creative implementation and strategic placement of traps can hamper the party or give an enemy the upper hand. More on that in a future post!

At the end of the day, traps aren't about tricking the party into taking damage and feeling good about how "clever" it was. Traps should be about using resources and creating interactive moments for the party to experience. Make traps visible!


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