Dungeon Delver’s Guide: It’s a Trap!
In EN Publishing’s upcoming Dungeon Delver’s Guide, we’re giving you every tool you need to build story-driven, atmospheric dungeons. And that means we have got to get traps right. Today I want to share the book’s trap-building philosophy, along with a few of the more than a hundred traps you’ll get when you Kickstart the book later this year.
Traps are a defining characteristic of dungeons. But too often, they feel like an arbitrary tax on the characters’ hit points. Done poorly, traps cause play to bog down as paranoid players poke and prod every door and passageway for unseen dangers. For these reasons, GMs and Narrators are often advised to use traps sparingly, or even steer clear of them entirely.
Throw that advice out the window!
Making choices and exploring the unknown are what make a dungeon fun. Telling players that their passive Perception has caused them to trigger, or avoid, a trap offers them neither choice nor the opportunity to explore. Traps are most fun after they’re discovered but before they’ve been neutralized. Should the rogue disarm the device? Should the wizard cast a spell? What does that inviting-looking lever do? With uncertain but probably dire outcomes on the line, every success and failure feels earned.
Just as combat tests both a character’s abilities and their player’s tactical skill, good traps allow for multiple solutions. A character invested in high Perception and Investigation, trap-specific abilities, and a set of thieves’ tools should be able to disarm any trap they encounter. At the same time, a clever player should be able to bypass the same trap simply by paying attention to their surroundings and playing a hunch.
Making a Dungeon Delver’s Guide-style trap is pretty simple to do. You can make traps fair and fun if you remember to telegraph every trap.
Telegraphing Traps
Players can’t see through their characters’ eyes or hear through their ears. As the Narrator, it falls on you to supply them with the information they need to make choices for their characters.
Besides the sensory information your descriptions provide, the level of detail you offer gives your players valuable information. The more details you lavish on a given location, the more important that location seems. This can work against you, such as when the players read too much into an offhand detail and as a result waste time investigating a random piece of furniture. But you can make it work to your advantage, as well. An area containing a trap or other hidden feature should be described with specificity, so that your players know it’s intended as a location they should explore, and not just an empty space that needs to be traversed on their way from A to B.
If possible, a location’s details should relate to the trap that it conceals. You don’t need to give so much information that you completely reveal the trap, but you should offer enough that the players can make the connection after the fact. If a trap has claimed the lives of previous explorers, there may be bones or other remains nearby—possibly charred if the trap creates a fiery explosion. If the dungeon’s denizens know how to avoid a trap, or need to visit it frequently to reset it, they may leave footprints. A trail of footprints that ends abruptly tells another story entirely! A good clue instills caution and increases tension, but doesn’t necessarily tell the players how to proceed. Instead, it asks a question: what do you do next?
What happens if you don’t telegraph danger in any way? Players learn that every location, no matter how seemingly insignificant, might harbor another such trap. Thus, their only sensible course of action is to examine every door, room feature, and length of hallway. The game can become a slow-paced grind.
Solving a Trap
Once a trap has been discovered, the real fun begins. How can the adventurers bypass the trap without triggering it?
Nearly every trap can be disabled with an appropriate ability check or two: characters with thieves’ tools proficiency, high Perception scores, and trap-sensing class features will get their chances to shine. Many traps can also be bypassed or disabled without a check. For example, pressing a hidden button might automatically disable a deadly device. Similarly, a character might use mage hand or a 10-foot pole to trigger a trap from a distance, staying clear of the trap’s range.
Our traps’ descriptions specify actions and spells that let a creature automatically avoid a trap’s dangers. Players might also think of other ways to bypass a trap. Based on how appropriate the solution is, you can decide that it doesn’t work, requires a check, or automatically succeeds. For instance, the description for a hidden pit trap lists avoiding or bridging the pit among its possible solutions. Casting fly and floating over the trap isn’t mentioned, but such a solution should automatically succeed. Walking over the pit on a tightrope, on the other hand, might require an Acrobatics check.
Want to try out some Dungeon Delver’s Guide traps? Here are some examples. These use Level Up’s Exploration Challenge format. To run them, you need to know the following:
Every ability check made while investigating or disarming a trap uses the DCs listed at the top of the trap description. The number before the slash is for solo checks, while the number after the slash is for group checks.
Attempting to disarm a trap can result in a critical success or a critical failure. A roll of 1, or a group check in which everyone fails, is a critical failure, while a roll of 20, or a group check in which everyone succeeds, is a critical success.
The italicized text, the description of the room, is the “telegraph”—the hint that something might not be quite right. You can read this text aloud or paraphrase it.
Reverse Gravity Trap
1st tier (constructed trap)
Challenge 4 (1,100 XP); DC 15/14
The walls are covered with floor-to-ceiling bookcases. On the ceiling, metal spikes hang down like icicles.
Gravity is reversed in this room. An unsecured creature or object that enters the room triggers a Failure. (Note: If this room contains creatures, they stand on the ceiling.)
Exploration. A Perception check or an examination of the bookshelves reveals that the books are shelved upside down against the tops of their shelves. The ceiling is 30 feet high. The bookshelves look easy to climb.
Books. As an action, a creature can make an Arcana or Investigation check to scan the bookshelves. On a success, the creature notices a spellbook (containing levitate or another 2nd-level spell) on a shelf across the room.
Spell Effect. This is a transmutation effect created by a 7th-level spell. A successful dispel magic disables the trap.
Possible Solutions
A creature can make an Athletics or Acrobatics check to climb along the bookcases. The check is made with advantage if the creature is upside down (i.e. right side up relative to the room’s gravity).
Critical Failure or Failure. The creature or object falls to the ceiling. Creatures that can levitate or fly don’t fall. The room’s ceiling is 30 feet high, so a creature that falls from the floor takes 10 (3d6) bludgeoning damage from the fall. A creature that takes falling damage also takes 10 (3d6) piercing damage from the spikes on the ceiling.
Once on the ceiling, a creature can move around the spikes safely but treats the area as difficult terrain.
Success or Critical Success. The creature moves through the room safely until the end of its turn.
Reverse Gravity Trap Variant: Random Gravity Trap
This room is identical in appearance to the Reverse Gravity Trap except that it has an upside-down door on the wall adjoining the ceiling.
Roll initiative. Each round on initiative count 20, gravity reverses direction. Each unsecured creature and object in the room when gravity changes falls up or down, as appropriate. Creatures take falling damage and spike damage when falling up, and falling damage only when falling down. A creature holding onto the bookshelves when gravity reverses must make a Dexterity saving throw or lose its grip.
Once a creature has noticed the location of the spellbook, the next two successful Arcana or Investigation checks reveal the locations of other valuable books, each containing a spell, information, or a Boon or Discovery.
Sword Guardian Trap
2nd tier (constructed trap)
Challenge 6 (2,300 XP); DC 16/14
A black metal statue stands in the middle of a hallway. The statue depicts a woman with four arms and the lower body of a snake. The statue holds swords in three of her hands; the fourth holds out a basket in your direction.
Pressure plates cover the floor within 5 feet of the side and rear of the statue. Stepping on a pressure plate or jostling the statue triggers a Failure. The pressure plates are disabled while the basket holds at least 10 pounds of weight.
Floor. An Engineering or Investigation check, or an examination of the floor, reveals that the floor next to and behind the statue is composed of pressure plates. The statue can be approached safely from the front.
Statue. Any investigation of the statue reveals that the words “Pay Your Respects” are engraved at the bottom of the basket. A character that makes an Arcana or Religion check recognizes the statue as a marilith, a type of demon. An Investigation check, or an examination of the statue, reveals that the marilith has articulated arms.
The statue is an object with AC 19, 75 hit points, and immunity to cold, lightning, fire, piercing, poison, and psychic damage. Damaging the statue without destroying it outright triggers a Critical Failure.
Possible Solutions
A creature can make a thieves' tools check to disable one pressure plate or one of the statue’s arms.
A creature can make a Strength check to break one pressure plate or one of the statue’s arms.
Critical Failure. The statue makes three melee attacks, each with a different arm. Each arm attacks with a +7 bonus, has a reach of 10 feet, and deals 9 (2d8) slashing damage on a hit.
Failure. As a Critical Failure, but only one arm attacks.
Success. One pressure plate or one arm is disabled. Disabling three pressure plates or arms triggers a Critical Success.
Critical Success. The trap is disabled.
Sword Guardian Variant: Sword Guardian Riddler
The message at the bottom of the sword guardian’s bowl is a riddle. An appropriate item placed in the bowl disables the trap; other items do not.
“Golden head bearing a crown, golden tail up or down.” The trap is disabled if one or more gold coins is placed in the bowl.
“Born in fire, formed in water, polished silver, end in slaughter.” The trap is disabled if a weapon made of iron or steel is placed in the bowl.