TRIGGERS
A trigge r is the circums tance that needs to take place to
acti vate the trap.
Decide what causes the trap to activate and determine
how the ch a racters can find the trigger. He r e are some
example trigge rs:
A pressure plate that, when it is stepped o n , acti-
vates the tr a p- A trip wire that springs a trap w hen it is broken, us u-
a lly w hen someone walks through it - A doorknob tha t activates a trap when it is turne d
the wrong way - A door or chest that trigger s a trap when it is opened
A trigger usually needs to be hidde n to be effective. Oth-
erwise, avoiding the trap is usually easy.
A trigger requires a Wisdom (P e rcept io n) check if
s imply spotting it reveals its nature. The characte rs can
foil a pit trap hidden by a leaf-covered net if t hey spot the
pit through a gap in the leaves. A trip wire is foiled if it is
spotted, as is a pressure plate.
Other traps require careful inspection and deduction
to notice. A doorknob opens a door when turned to the
le ft , but activates a tra p whe n turned to the rig ht. Such a
subtle trap requires a successful Inte lligence (Investiga-
tion) c heck to notice. The trigger is obvious. Understand-
ing its nature is not.
The DC of the check, regardless of its type, depends
on the s kill and care take n to conceal the trap. Most
traps can be detecte d with a successful D C 20 check,
but a crudely made or has tily built trap has a D C of 15.
Exceptionally devious traps might have a D C of 25.
You mus t then put some thought into what t he c har-
acters learn with a successful check. In most cases, the
check reveals the t rap. In other cases, it uncovers clues,
but foiling the t rap still requires some d eduction. The
characters might s ucceed on the check but s till trigger
the trap if they don't unde rstand w hat they h ave learne d.
EFFECTS
Designing a tra p's effects is a straightforward process.
The tables for saving throw DCs, attack bonuses, dam-
age, and the like give you a starting point for most sim-
ple traps that deal damage.
For traps with more complex e ffects, your best start-
ing point is to use the Spell Equivalent by Level table to
find the best matc h for your trap's intende d effect. Spells
are a good starting point because they are compact
pieces of game desig n that deliver specific effects.
If you are us ing a spell as a starting point, check to see
if you need to tweak its effects to fit the trap's nature. For
instance, you can easily change the d a mage type a s p ell
de livers or the saving throw it requires.DISARMING A SIMPLE TRAP
Only one successful ability check is require d to disarm
a simple trap. Imagine how your tra p operates, and then
think about how the characters could overcome it. More
than one kind of ability c heck might be possible. Some
traps are so poorly concealed that they can be discov-
ered or circumvented without active e ffort. For instance,
a hidde n pit trap is effectively disarme d as soon as thecha racters notice it. After that, they can simply walk
around it, o r they can climb down one side, walk across
t he bottom of the pit, and climb up the other side.
Once you determine how a trap can be disarmed or
avoided, dec ide the appropriate ability a nd skill com-
binations that characters can use. A Dexterity check
us ing thieves' tools, a Stre ngth (Athletics) c heck, and a n
Inte lligence (Arcana) check are all commonly used fo r
this purpose.
A Dexterity check using thieves' tools can apply to any
trap that has a mechanical e lement. Thieves' tools can
be used to disable a trip wire or a pressure plate, disas-
semble a poison needle mechanism, or clog a valve that
leaks poisonous gas into a room.
A Strength check is often the method for thwarting
tra ps that can be destroyed or prevented fro m operating
thro ugh the use of brute force. A scything blade can b e
broken, a sliding block can be held in place, or a net can
be torn apart.
A magic trap can be disabled by someone who can
undermine the magic used to power it. Typically, a s uc-
cessfu l Intelligence (Arcana) check enables a character
to figure out how a magic trap functions a nd how to ne-
gate its effect. For instance, the character could discover
t hat a statue that belches a jet of magical flame can be
disabled by shattering one of its glass eyes.
Once you k now what kind of c heck is called for, you
then determine what happens on a failed attempt to dis-
able the trap. Depending on the kind of check involved
and the nature of t he tra p , you might determine that any
faile d c heck has negative consequences- usually involv-
ing the triggering of the t rap. At other times, you could
assig n a numbe r t hat the check must exceed to prevent
the trap from going off. If the total of the c heck is equal
to or lowe r tha n that number, the trap activates.PLACING A SIMPLE TRAP
Context and environment a re critical when it comes
to prope rly locating a trap. A swinging log tra p that's
meant to knock character s aside is a mere inconve-
nience on a typical forest path , whe r e it can be easily
circumvented. But it's a potentially deadly hazard on a
narrow trail that hugs t he side of a towering cliff face.
Choke points and narrow passages that lead to im-
portant places in a dungeon a re good spots for traps,
especially those that serve as a larm s or restraints. The
goal is to foil or de lay intruders before they can reach a
c ritical location, giving the dungeon's denizens a chance
to m ount a defe nse or a counterattack.
A treasure c hest, a door leading to a vault, or any other
obstacle 'o r container that bars the way to a valuable
treasure is the ideal location for a slaying trap. In such
instances, the trap is the last line of defense against a
thief or intruder.
Alarm traps, s ince they pose no direct phys ical
threat, are appropriate for a reas that are a lso used by
a dungeon's denizens-assuming the residents know
about the trap and how to avoid setting it off. Accidents
can happen , but if a goblin stumbles inside its den and
activates an a larm trap, there's no real harm done. The
alarm sounds, the guards arrive, they punish the clumsy
goblin, and they reset the trap.CHAPTER 2 I DUNC EON MASTER'S TOOLS