Traps can be found almost anywhere. One wrong step in an ancient tomb might trigger a series of scything blades, which cleave through
Armor and bone. The seemingly innocuous vines that hang over a cave entrance might grasp and choke anyone who pushes through them. A net hidden among the trees might drop on travelers who pass underneath. Unwary adventurers can fall to their deaths, be burned alive, or fall under a fusillade of
Poisoned Darts.
A trap can be either
mechanical or
magical in nature. Mechanical traps include pits, arrow traps, falling blocks, water-filled rooms, whirling blades, and anything else that depends on a mechanism to operate. Magic traps are either magical device traps or spell traps. Magical device traps initiate spell effects when activated. Spell traps are spells such as
Glyph of Warding and
Symbol Spell that function as traps.
Traps in Play
When adventurers come across a trap, you need to know how the trap is triggered and what it does, as well as the possibility for the characters to detect the trap and to disable or avoid it.
Triggering a Trap
Most traps are triggered when a
creature goes somewhere or touches something that the trap's creator wanted to protect. Common triggers include stepping on a pressure plate or a false section of floor, pulling a trip wire, turning a doorknob, and using the wrong key in a
Lock. Magic traps are often set to go off when a creature enters an area or touches an
object. Some magic traps (such as the
Glyph of Warding spell) have more complicated trigger conditions, including a password that prevents the trap from activating.
Detecting and Disabling a Trap
Usually, some element of a trap is
visible to careful inspection. Characters might notice an uneven flagstone that conceals a pressure plate, spot the gleam of light off a trip wire, notice small holes in the walls from which jets of flame will erupt, or otherwise detect something that points to a trap's presence.
A trap's description specifies the checks and
DCs needed to detect it, disable it, or both. A character actively looking for a trap can attempt a
Wisdom (
Perception)
Skill Check against the trap's DC. You can also compare the DC to detect the trap with each character's
Passive Wisdom (Perception) score to determine whether anyone in the party notices the trap in passing.
If the adventurers detect a trap before triggering it, they might be able to disarm it, either permanently or long enough to move past it. You might call for an
Intelligence (
Investigation)
Skill Check for a character to deduce what needs to be done, followed by a
Dexterity (
Sleight of Hand) check using
Thieves' tools to perform the necessary sabotage.
Any character can attempt an
Intelligence (
Arcana) check to detect or disarm a magic trap, in addition to any other checks noted in the trap's description. The
DCs are the same regardless of the check used. In addition,
Dispel Magic has a chance of disabling most magic traps. A magic trap's description provides the DC for the
Ability Check made when you use dispel magic.
In most cases, a trap's description is clear enough that you can adjudicate whether a character's actions locate or foil the trap. As with many situations, you shouldn't allow die rolling to override clever play and good planning. Use your common sense, drawing on the trap's description to determine what happens. No trap's design can anticipate every possible action that the characters might attempt.
Sometimes, a character can discover a trap without making an
Ability Check if an action would clearly reveal the trap's presence. For example, if a character lifts a rug that conceals a pressure plate, the character has found the trigger and no check is required.
Foiling traps can be a little more complicated. Consider a trapped treasure
Chest. If the chest is opened without first pulling on the two handles set in its sides, a mechanism inside fires a hail of
Poison needles toward anyone in front of it. After inspecting the chest and making a few checks, the characters are still unsure if it's trapped. Rather than simply open the chest, they prop a
Shield in front of it and push the chest open at a distance with an
Iron rod. In this case, the trap still triggers, but the hail of needles fires harmlessly into the shield.
Traps are often designed with mechanisms that allow them to be disarmed or bypassed. Intelligent monsters that place traps in or around their lairs need ways to get past those traps without harming themselves. Such traps might have hidden levers that disable their triggers, or a secret door might conceal a passage that goes around the trap.
Trap Effects
The effects of traps can range from inconvenient to deadly, making use of elements such as
Arrows, spikes, blades,
Poisons, toxic gas, blasts of fire, and deep pits. The deadliest traps combine multiple elements to kill, injure, contain, or drive off any creature unfortunate enough to trigger them. A trap's description specifies what happens when it is triggered.
The
Attack bonus of a trap, the save
DC to resist its effects, and the damage it deals can vary depending on the trap's severity. Use the Trap Save DCs and Attack Bonuses table and the Trap Damage Severity by Level table for suggestions based on three levels of trap severity.
A trap intended to be a setback is unlikely to kill or seriously harm characters of the indicated levels, whereas a dangerous trap is likely to seriously injure (and potentially kill) characters of the indicated levels. A deadly trap is likely to kill characters of the indicated levels.
Trap Save DCs and Attack Bonuses
| Trap Danger | Save DC | Attack Bonus |
|---|
| Setback | 10-11 | +3 to +5 |
| Dangerous | 12-15 | +6 to +8 |
| Deadly | 16-20 | +9 to +12 |
Trap Damage Severity by Level
| Character Level | Setback | Dangerous | Deadly |
|---|
| 1st-4th | 1d10 | 2d10 | 4d10 |
| 5th-10th | 2d10 | 4d10 | 10d10 |
| 11th-16th | 4d10 | 10d10 | 18d10 |
| 17th-20th | 10d10 | 18d10 | 24d10 |
Trap Spell Equivalent by Level
| Character Level | Setback | Dangerous | Deadly |
|---|
| 1-4 | 1st | 1st | 2nd |
| 5-10 | 1st | 3rd | 6th |
| 11-15 | 3rd | 6th | 9th |
| 16-20 | 6th | 9th | 9th + 5th |
Complex Traps
Complex traps work like standard traps, except once activated they execute a series of actions each round. A complex trap turns the process of dealing with a trap into something more like a
Combat encounter.
When a complex trap activates, it rolls
Initiative. The trap's description includes an initiative bonus. On its turn, the trap activates again, often taking an
Action. It might make successive
Attack against intruders, create an effect that changes over time, or otherwise produce a dynamic challenge. Otherwise, the complex trap can be detected and disabled or bypassed in the usual ways.
For example, a trap that causes a room to slowly flood works best as a complex trap. On the trap's
Turn, the water level rises. After several rounds, the room is completely flooded.
Sample Traps
The magical and mechanical traps presented here vary in deadliness and are presented in alphabetical order.
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