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  • Writer's pictureAaron K

The 4 Elements of Good Traps

Hey Reader!

So we did a post a few weeks ago talking about how to make more interesting traps, and since I've been running more dungeons for my players recently, I wanted to take a few minutes to talk through the four principle elements of a trap, and how you can use each element to make the game more interesting for your players.

A lot of people assume that there are only two parts to a trap: the trigger and the trap itself. And that makes sense, as those are the two most important parts. But there are two other aspects that lead to the making of a gripping and powerful trap, and that's what we want for our games.

We will walk through each part, giving examples of how to do this well.

Part 1: The Setting

A lot of people breeze past the setting, which is part of why traps feel like a "gotcha" element in most dungeons. Your setting description shouldn't drone on and on, but it should convey the pertinent details to help with the avoiding/mitigation of the trap. Think of it like this: a setting description should be like a kilt: long enough to cover the subject, but short enough to be functional.

So for example, this is a bad trap setting:

"You continue down the passageway, and the rough stone suddenly changes to slabs of cut stone, some raised higher than the others. What do you do?"

This conveys part of the setting, to be sure: we've indicated that there might be pressure plates on the floor, but we have also restricted the agency of the players to actions involving footing because all we know is the nature of the floor. Consider the following which only adds one more sentence:

"You continue down the passageway, and the rough stone suddenly changes to slabs of cut stone, some raised higher than the others. You look up and see that the ceiling is still rough and jagged with the natural stalactite formation of the tunnel, and on both walls are pictographs of ancient warriors with drilled holes where their mouths should be. What do you do?"

We have a three-dimensional description now: we know what the floor, walls, and ceilings look like, and the party starts putting together the aspects of the trap. The party can now assess whether they want to climb along the ceiling (risking the sharp rocks, difficult handholds, and/or dangling legs that come with it), try to use the holes in the walls as fingerholds and climb the wall, etc. They have a good idea of what is around them in all dimensions, so they can act accordingly.

But do they? This is the joy of giving thought to your trap setting: it gives an accurate view of the setting, but the players impute meaning on various aspects. Let's see how.

Part 2: The Trigger

This is the "click" aspect of the trap: it's the pressure plate, the tripwire, the glowing of a magical glyph, or walking in range of a peephole where a spirit, wight, or other creature that doesn't require sleep or nourishment can watch for intruders.

Everyone pays attention to the trigger, but that also means that triggers can be boring because once we find the trigger, we are pretty sure we know how to disarm or evade the trap. So my recommendation: give them multiple triggers.

Now note that this is not, "make traps that require multiple ways to disarm them," as that is 1) impractical for most technology eras, and 2) just asking for player ire. You should instead present multiple tell-tale signs that could be taken as triggers and see how the party approaches them, and in what order.

So in the example above, the obvious trigger are the uneven stones: these might be pressure plates in the floor that would cause, say, darts to shoot from the holes in the wall. But what if the trigger is actually the holes in the wall (which are peepholes for goblins to look through), and the stones are uneven because of age, lack of repair, or lack of skill in making them?

I suspect that there is a hierarchy of trigger investigation; I haven't done a study on it, but I'm guessing it goes something like Magic Glyph - Tripwire - Pressure Plate - Peephole - Disguised Lever - False Wall/Floor. You can use this to your advantage: put several of these aspects in a trap, and let them discern which ones are triggers for traps and which ones just look like triggers for a trap.

Part 3: The Trap

This is the mechanism that we call "the trap." It's not the damage or consequence of the trap, though (we'll get to that next), and that's where a lot of traps fall flat. If the trap and the consequence are the same, you lose a lot of the tension in the scene because the resolution of the trap is so fast.

I recommend seeing the trap as the mechanism, not the consequence. Draw it out: a party member knocks over a skeleton, causing it to fall and reverberate throughout the cavern. A person steps on the wrong slab, and they hear the rumbling of a large boulder coming their way. A person cuts a tripwire and it releases suspended weights that come crashing down on the group (because the person who built this place was a rogue and knew that people would try to cut tripwires to keep from stepping on them, so the maker also attached them to suspension weights).

When you separate the trap and the consequence in your mind it heightens the trap for your players. Suddenly making a reflex save, or dodging a blade, or whatever might come as part of the trap, not only has a place in the resolution of the trap (as we are intentionally slowing this part down to build the tension), but it also keeps a question lingering in the minds of your players: "So...what's going to happen to me?"

And we want them to dwell there. Just for a little while.

Part 4: The Consequence

The consequence is the damage or detriment of the trap, and it's something that a lot of people gloss over which is part of why traps can seem boring. This could be as simple as a blade or dart coming out of the wall, or a boulder rolling down from the ceiling, or a magical hex that grabs hold of you before a dart or blade comes out of the wall. But the end goal is the same: this is what they've been dreading.

The advantage of thinking of the consequence as separate from the trap is that it also opens up new opportunities for what the trap can look like. If the consequence is just a freestanding thing, not actually part of the trap, the party will fixate on the consequence instead of the trap itself, increasing the chance that the party triggers the trap unawares.

Perhaps there's a vat of acid in a room that slopes inward toward the vat, and the party looks around and thinks, "Oh no: the trap is the vat of acid: we should try not to fall in," they will likely hug the walls of the room to avoid the vat. This means that the opening of a blade trap might be seen as a handhold, designed to give the party a chance to hold onto something in the wall to keep from sliding into the vat. Instead it's the trigger: we want the party to put their hands here, so we paint it as a solution to the consequence.

This then springs the trap, the trap causes the character to jump back, and that sends them into the vat (the consequence). Had we fixated on the trap being the vat, we would have missed the chance for this. So we break them up in our mind, using the aspects of the trap to push things toward the consequence, sometimes from odd angles.

And you can do this with a lot of different types of traps. Perhaps there's a magical glyph that, when people are within 10 feet of it, it explodes. The party identifies the glyph as an exploding glyph, and attempts to avoid it. But in the process of avoiding the exploding glyph they hug the roof and find that the stalactites are fake and designed to come loose from the ceiling, dropping them onto the glyph.

And then, of course, there are always deceptions. Perhaps the raised cobblestones are the safe ones, or maybe the holes in the wall are actually handholds because the whole floor is a false floor, and you aren't supposed to step on any of the stones. Or maybe the large boulder above the door is supposed to block a gout of flame that can be triggered by movement, so you're supposed to trigger the boulder and then follow it as it rolls along. There's a lot of ways you can run deception aspects of traps, with your players imputing danger to the trap element that isn't really there.


To tie it all together, here's an example from a dungeon I recently ran. My players came across a straightforward trap: a massive tangle of briars that, if they tried to go through it, would tear their legs to shreds with its sharp thorns (2d4 piercing damage for each 5ft of movement). It went for a good long while (easily 60-70ft), so even the tanks of the party didn't want to cross it. They were also on a clock so cutting their way through with axes could work, but it would cost them, and while they could have burned the place with a few well-placed spells, they didn't want to burn through (hehe, see what I did there? Okay) that many resources that quickly.

They also knew, however, that there was a ledge about 10ft off the ground that was relatively wide - wide enough that you could stand up there and walk along it with some level of confidence. It would require a climbing check (and failures would result in you falling into the briar patch), but it was an option.

(Notice how there are several ways to get past the consequence of the trap, which keeps player agency alive. The players conflated the consequence of the trap for the trap itself, though, which is what caused them to spring the trap, as you'll soon see)

Not surprisingly, the party opted to try their hand at scaling the ledge. They sent a very athletic character up first with a rope, and after reaching the top that person attached the rope to the wall and started helping the others up. As they got the group on the ledge, they walked along it, suddenly discovering false walls at various intervals (the trigger). From behind the walls came the wights (the trap), which attacked them ferociously, reducing their max hit points if they stayed in melee range, and pushing them into the briar patch (the consequence) where they could then be shot by the longbows from the wights.

It's a very simple trap, but it was sprung entirely because the party assumed that they were bypassing the trap by using the ledge. But they weren't: they bypassed the consequence, not the trap itself. The consequence set them up to trigger the trap, and then the trap made good on the existence of the consequence.

If you design traps like this, your players will be constantly on the edge of their seats because they honestly won't know anymore what you are doing. And that is the heart of tension that we want from traps.

Until next time,

Aaron K


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