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Traps are a defining part of theDungeons & Dragonsexperience but can be hard to use well. An effective trap will instantly kill its target without being detected beforehand, but this isn’t very fun for the player who triggered it and now has to sit out the session writing up a new character.
Making use of traps in Fifth Edition is a balancing act between letting the players see and play around the threats they detect while still keeping the game moving at a good pace and maintaining an appropriate level of challenge that will be specific to the playstyle and personalities of your group.
How To Design Traps
There aretwo halves to the design process, with the first focused on the game mechanicsand the second being the implementation into the world and setting. The Dungeon Master’s Guide (chapter five, adventure environments) has some guidance on the first butleaves the implementation largely at the Dungeon Master’s discretion.
The best place to start with is from the concept of what you want the trap to do and then work out how that would bear out mechanically. Consider the following questions:
Designing The Mechanics Of A Trap
The DMG divides traps into four level bands, which result in avery broad range of effects depending on where the players fall within that. The weakest level one trap can incapacitate a first-level player from full hitpoints but mildly inconvenience a fourth-level character. If you want to use traps at these earlier levels, you still can but may want to weaken the damage dice accordingly from the d10 recommended at baseline.
1
2
3
D8
From level four and beyond the damage severity table works a lot better, and you can use them as listed. This adjustment focuses on avoiding that un-fun but memorable scenario of a player losing their first character within five minutes of starting the game. It helps that from fifth level, you have revivify and otherhealing tools to prevent or reverse instant deaths from traps.
For traps that can activate multiple times, you’ll typically want toreduce the damage level by one rank. you may keep the save DC and attack bonus of the original rank.
Use this for traps thatactivate repeatedly when a cue is met(such as a burning floor trap that activates each time it is stepped over) or for traps that activate at set intervals (such as a spinning blade that hits everyone in an area at the start of a combat round).
There are other effects that you may apply to a trap besides a flat amount of initial damage:
Persistent damage
A trap that launches alchemist’s fire,dealing fire damage until extinguished.
A creature takes 1d4 fire damage each turn start until itmakes a DC10 dexterity check to douse the fire.
Debuff
Aglyph of warding contains a spellsuch as slow or hold person instead of a damaging effect.
Apply the spell effect with thesame saving throw DCs as the glyph creator (but without concentration).
Poisons
Adart trap might be coated in drow poisonor similar toxins.
Apply the samesaving throws and effects listed on the poison. For Drow Poison that would be DC13 constitution or be poisoned for one hour (and unconscious if failing by five or more).
The initial damage of the dart could be setback level, but might have theattack bonus of a dangerous trap.
Alarm
A tripwire can set off bells orknock over objects to make noise.
Combat initiates after a few moments ifenemies are in range to hear the alarm.
If the party did not detect the trap,they may be surprised.
How To Use Traps
Implementing Traps
Making the traps you design cohesive to the setting, enjoyable to interact with, and having meaningful results for both evading and tripping them are all important considerations that are not explained in detail in the Dungeon Master’s Guide.
As the rules are written,a trap is only detected if the character is actively searching for itor takes actions that make it impossible to conceal the trap. This can slow gameplay to a crawl if the players check for pressure plates underneath every rug and open every door using Mage Hand from behind a tower shield with attacks readied for an ambush.
There are a few ways to implement traps while retaining the challenge and puzzle and avoiding the slog of making players meticulously describe the process of examining every floor tile before stepping on it:
Effect
Roll For Them
When the players enter an area containing traps,make hidden investigation or perception checks on their behalf. Notify them of any traps found from these rolls.
This gives a prepared party good chances to spot traps ahead of time without requiring them toslow down and manually state they are investigating a scene.It also increases the value of feats that aid in detecting traps, such as alert.
It can increase the burden on the DM, especially if you are not using a virtual tabletop that has this functionally coded in automatically.
On a failed roll, the party will still feel blindsided by the traps becausethey were not aware they had failed the secret roll.
Foreshadowing
Telegraph that an area is going to include traps, either byhaving one already be sprungor having a stray rat get incinerated in sight of the party
Thisfeels the fairest from the side of the players.They are told there is a threat for them to avoid, and they are given every opportunity to identify it or take countermeasures.
You can incorporate this method into the gameplay bygiving the players a wand of Find Trapsand discussing that they use it at regular intervals without having to slow down the game and actively state they are casting the spell
Thisremoves some of the tension of searching for traps, as the party will always know that there is at least one to find when prompted.
Traps Only Appear In Combat
Only use traps that interact during and as part of combat. During exploration, they are either inactive orthe party is assumed to move slowly and carefullyto not trigger them.
This forces decisions on when to spend actions looking for and disarming traps or toengage with the more direct threats posed by enemies.
Sometraps might catch enemies in the crossfire, which is entertaining.
This favours the use of more complex trapsthat can be time-consuming to design and implement.
How To Describe Traps
Traps should be described as part of the environment, in a way that matches the aesthetic of the scene and the people using them. The floating skull of a demi-lich has better things to do thandig a twenty-foot pit through solid rock and fill the bottom with spikes.
The local cave troll isn’t going to have thepowdered gemstones needed to set up glyphs of wardingaround their lair. Using the right types of trap for the scenario can help immersion as well as gameplay: The players will know what types of traps to look for depending on the architecture and enemies.
Wilderness Ambushes
Snares, pitfalls and othersingle-use traps that limit or restrict movement.
Blends into and may potentially becrafted out of the local environment and foliage.
Urban Ambushes
Glyphs of Warding and other magical traps that can beprogrammed to only target a specific person.
Quick to set up trapslike snares and tripwires, perhaps with afocus on incapacitating instead of killing the target.
A player scouting out the scene ahead of timemight spot the spellcaster setting up these traps.
Most factions willavoid using explosive tripwires in a crowded marketplace, for example.
Dungeons
Complex traps thatdo not need to be reset manually.
Dart traps and spinning blades work well with the aesthetic of a dungeon and can beincorporated into the architecture.
This type of trap should havea way of bypassing or disabling it,used by the dungeon’s inhabitants.
Boss Arenas
Glyphs of Warding that cast haste, protection spells and provide healing to the boss.
Complex traps that target specific positions on a battlemap,using a pattern that could be memorised by the boss and his minions.
Glyphs of Warding allow a prepared combatant toevade the normal limitations on concentration spells.
A smart player mighttake advantage of complex traps by shoving enemies into them.
It can be somewhat immersion-breaking to describe a giant swinging log, spinning blade, or flamethrower that blasts into the halfling rogue who promptly springs back up because he had enough HP to survive.
If a trap description would logically result in a player instantly dying if it hit them, insteaddescribe a failed saving throw as a near miss, grazing them or throwing them off balance with visible but survivable injuries.
Hitpoints are an abstraction of a character’s ability to avoid fatal injury and this means they can be lost without actively taking an injury. A trap that descriptively has failed to draw blood might still mechanically harm a character by shaking their resolve, damaging their armour, or inflicting minor injuries that make dodging harder.
