On Wandering Monsters, Part 4: Wandering Traps?

I’ve always hated traps.

There, I said it. Aside from the occasional
booby traps placed by the kobolds and the Ettercap in Into the Living Library, in my
entire GMing career, I’ve only ever used a single trap—also in Into the Living Library—and it was
really more of a plot device than anything else. It was a clearly marked death
trap to encourage the party to turn around and do some exploring and
roleplaying to find a bypass. The trap was a lock; Leonard’s Lightning
Redirector was the key.

Traps are boring. The Rogue makes a Perception Check (and fails it, because
Rogues routinely have terrible Wisdom), then passes their ensuing Reflex save,
and we all move along. Alternatively, the save is failed, and the Rogue takes
damage, which no action or decision from the Player could have avoided in any
case. Some amount of damage will just be taken and the dice will decide how
much; it’s not particularly engaging or interactive. The party recognizes this is
the cost of doing business and deducts a bit more of their profit into healing
potions.

Traps are literally business expenses. Taxes.

But I used to think the same thing about
Wandering Monsters, and lately I’ve come to love those. So far, most of what
I’ve written in this series have been things that have been percolating in my
mind for some time now and tested in Into the Living Library and City of Eternal Rain, but this is largely
new territory.

Can our Wandering Monster table include
traps?

In Living
Library, some minor traps were on
the table as “hints,” but I’m envisioning something much more
comprehensive. If traps are sufficiently foreshadowed—as Wandering Monsters can
be—they will feel less random, and therefore less like wastes of time. If they
aren’t settled solely by a series of dice rolls, but rather decisions (that may
include and affect dice rolls), they will feel less punitive.

“Wandering Traps” don’t
necessarily replace bespoke, custom-placed traps, just as Wandering Monsters
don’t replace designed set-piece encounters. They can work side-by-side,
simulating an active dungeon ecology while reducing GM prep work as a dungeon will
only need a handful of unique, hand-placed traps as the procedurally-placed Wandering
Traps can pick up the slacks.

This post will be an experiment in adding
traps as “creatures” to the Wandering Monster table described in the
last post, which looked like this:

(The previous, simplistic attempt at
including traps into this table can be seen in the Hint column for the Shepherd
of Spiders (an Ettercap) and for kobolds). Let’s see if we can do better.

Traps as Landmines

In the movies, landmines never just explode. Rather, a character steps on
one, then realizes what they’ve done. A tense scene develops wherein the victim
and his comrades attempt to defuse the mine, or trick it somehow, into letting
the victim step off of it without detonating. Do they dare split up and go for
help, leaving the victim all alone?

In many ways, landmines were designed with
this aim in mind, as rather than simply killing one person, a single mine can
potentially delay an entire group for hours, which in many contexts is more
valuable.

What if in D&D, encountering a trap
doesn’t immediately mean that it goes off, but rather, the party (in
particular, whoever is in front) finds themselves on the verge of detonating the trap, and then has to figure out how to get
out of their predicament?

For traps, instead of an ENCOUNTER column, I’ll put in a NOBODY MOVE column. This entry
represents some poor soul suddenly realizing they’re in harm’s way, that is,
standing on the pressure plate (“don’t even breathe or you might set it off!”), with their foot on the
tripwire, or standing on a slowly-creaking false floor above spikes. If they
stay perfectly still, the party might
be able to devise a solution. As this replaces ENCOUNTER, it must be the most immediately dangerous roll, so other
columns ought to be foreshadowing or less-immediate threats.

Spotting Traps

Unless the party is actively searching for
traps, spotting them should be incredibly difficult. We can safely make this a
hard check, because, as mentioned earlier, failing no longer results in automatically
setting off the trap. A WISDOM (PERCEPTION) check of 20, or an INTELLIGENCE
(INVESTIGATION) of 15 if they are actively searching, is probably a good DC.
Success should be uncommon but not impossible.

However, spotting traps is almost as fun as
getting caught up in them, as it also leads to interesting choices—does the
party press ahead and risk setting off the trap, attempt to disarm it, or take
another route and hope that they can bypass it?

Now, we can lower the DC, but that runs the
risk of meaning higher-level and higher-wisdom characters will always spot traps, which is boring. So
how about we just add another column to the table wherein the party spots a
poorly-hidden trap? TRAP AHEAD can
be our second column, representing exactly what it sounds like—the party
notices a poorly-hidden trap blocking their path, and must choose to brave it
or turn back.

Add Some Foreshadowing

We’ve figured out how traps are spotted,
but unless the party actually knows what triggering the pressure plate will do, they won’t know how afraid to be.
We need to tell the party that the trap shoots poison darts without actually
shooting them with poison darts—this is where our HINT columns come in. We’re still short a column, so let’s extend
this principle further with a FALSE
ALARM column—the party encounters a trap, but it’s either a dud or
malfunctioning. The existence of duds has the added advantage of making them
never know if the trap in front of them is ‘live’ or not.

Putting it Together

Here’s an example of how this might come
together. For a finished product, the six creature slots and both trap slots
would be filled in, similar to the table from Into the Living Library.

Alongside the entries in the table, as with
Wandering Monsters, a paragraph or so of description kept nearby is needed to
include a little more detail, and rules like DCs and damage.

Flame Jets. This trap is triggered by a pressure
plate—a disguised flagstone in the floor that depresses with weight placed on
it, causing the arrows to fire. The mechanisms are old, faulty, and weren’t
originally made by a society with particularly advanced engineering, so the
same plate can be walked over many times before it finally decides to trigger, blasting
scorching jets of flame through hidden vents in the walls. If the trap is
triggered, anyone on the pressure plate, anyone attempting to disable the trap,
and anyone else within 10 feet must make a REFLEX SAVE of 12 or better or take
2D10 fire damage. Because the pressure plate is faulty, it may not necessarily
be the partymember in front who realizes their danger—choose your victim at
random from among the party.

We can just append the traps to the end of
the Wandering Monster table. If the GM rolls a D6 (the Creature Die), only
creatures can be encountered; on a D8 (the Threat Die), higher rolls result in
traps. Perhaps D8s are rolled when the party enters new areas (that might
contain traps) while D6s are rolled when the party backtracks, or enters an
empty room. Areas that the party will spend more time in should have more
monsters and traps and use larger dice, though the balance of how many monsters
vs. how many traps will depend on the nature of the dungeon. For example, a
dungeon with a D6 creature die and a D12 threat die will have 6 creatures and 6
traps (with 31 possible unique rolls) will feel very different from a D10
creature die and a D12 threat die, which has 10 creatures but only 2 traps. A
larger number of monsters and traps will mean more variety, but also a greater
likelihood of encountering unforeshadowed traps and monsters. Consider instead dividing
the dungeon into smaller chunks, each with corresponding (smaller) tables, such
as a D4 creature die and a D6 or D8 threat die.

Disarming Traps

If the party is in a place where they’re
disarming a trap, it either means that they’re very nervous (because someone is standing on the trigger), or were
fortunate enough to spot it before anyone got in the way. The 5th
edition DMG provides scant rules on disarming traps, so I’ll write some of my
own to fit this new system. The DC to disarm the trap should be fairly low, as
the consequences of failure are quite high and it’s probably going to be the
same PC (i.e., the Rogue) who disarms every trap, and as such suffers the most
for failure. An actual plan for disarming the trap has to be presented—simply rolling
a die isn’t enough, as it puts us right back into “roll dice and take
damage, then move along” territory. Feel free to adjust the DC for dungeons
aimed at higher-level play. Similarly, the rarer the traps, the higher the DC
should be, as you run less risk of piling damage unfairly on the Rogue (who can
take one or two trap hits, but not dozens). Correspondingly, for dungeons with
many traps, I would keep the DC quite low. Here’s a first pass of the specific
rule I would use for this:

If an armed
trap is discovered (either from a “NOBODY
MOVE” or a “TRAP AHEAD”
roll), the party will often try to disable it.

To disable
the trap, someone first must devise a plan—simply saying “I try to disable
the trap” and rolling a die won’t do. Instead, the Player might declare
that their character will try to wedge a knife under a pressure plate to
prevent it from triggering, or pack a scythe blade’s wall slit full of rocks to
block it from swinging, or plug a dart trap with wax to gum up the mechanism, or
the like. Creativity in this step should be encouraged.

After
devising a plan, a skill check must be made. Normally, this is a Dexterity
check using Thieves’ Tools, but depending on the plan, other abilities, tools,
or skills might come into play. Regardless of the skill used, a roll of 12 or
better is a success. A particularly good plan provides advantage, while an
uninspired or foolish one incurs disadvantage. If the Party has encountered an
identical trap previously and has closely examined its workings, the Player
also gets advantage on this roll.

A successful
check disables the trap, allowing the Party to bypass it safely. Depending on
the plan presented, the trap might be permanently destroyed or simply
temporarily bypassed. A failed check sets off the trap, which can harm whoever
tried to disarm it, anyone standing on the trigger, and potentially others as
well. If the trap remains a hazard after the party has left, the GM should be
sure to note on her map where the trap is and what state it’s in, in case the
party returns.