Puzzle Do's and Dont's + Some Examples

You probably use puzzles in your dungeons.  I have advice for that.

DON'T Use Video Game Puzzles

Video game puzzles are highly visual, quickly communicate geometry and orientation, and often let you pack a lot of information onto the screen at one time.

DMs mostly communicate things verbally.  The bandwidth is a lot less.

I love the puzzles in Zelda, The Witness, and Portal, but none of them translate well to tabletop.  The puzzles in the Witness would require you to give your players a lot of handouts (which is fine, in moderation), and Zelda-style block pushing puzzles often require you to have a grid where you track stone placement, open doors, etc.  

A good example of a good Zelda puzzle is one where you maneuver a bunch of mirrors to bounce a ray of light through three crystals.  

It's almost as bad as when the DM hands you a sudoku when you walk in the room.  Or math problems.  Ew.

DO Use Escape Room Puzzles

Escape room puzzles are usually about pattern recognition, and/or searching an environment until you find a pattern.  (The pattern recognition puzzles in Breath of the Wild, such as the three tree puzzles, are an example of this.)

Another concept: encoding patterns in sounds.  (In Lair of the Lamb, there water that drips off a fish statue with a drip-dripdrip-drip-dripdrip pattern.  Another fish statue holds a tumbler where the players can open a door by inputting 1-2-1-2.)

Escape rooms also go wild with shadow casting, or spotlights illuminating significant objects, etc.

Some examples here.

MAYBE Use Riddles

I enjoy them, but most of the time the players either figure it out in 3 seconds or they never figure it out.  Neither is satisfying.

DO Puzzle Dungeons Rather Than Puzzle Rooms

I realize that some people will chime in with "but puzzle rooms break up the monotony of the combat rooms and social challenge rooms".  

To them I reply "combat, conversation, and exploration are already puzzles in a well-designed OSR game.  You don't need puzzle rooms to break up the monotony, because the puzzles never really stop.  How do we get past this chained-up basilisk?  Are these goblins lying to us?  How do we open this sealed door?"

A dedicated puzzle dungeon (or at least, a few puzzle rooms linked together) has these advantages.

1. You can build upon an existing knowledge base.  I you look closely at a game like Portal, you'll realize that most of the game is just a tutorial.  Each level teaches you one more thing about how to use your portal gun.  You build upon the previous knowledge and expand your knowledge base gradually.

2. It allows you to create linked puzzles, such as requiring you to use knowledge or tools from an earlier room.

3. Puzzles can be arranged by difficulty, with the harder ones in the back.

4. It allows you to set it aside from the rest of the dungeon, so the players don't feel like the puzzle is something that they need to get through.  Instead, they can choose to go to the puzzle section where they already know to pay extra attention to tiny details and slake their thirst of puzzles.  If they don't want puzzles, they can leave.

DON'T Use Puzzles if You Need Players to Solve Them

Puzzles are unreliable.  Sometimes players get frustrated and walk away.  Sometimes people don't want to do puzzles.  Sometimes the answer is simply outside of their reach.

If you need the players to get to the final boss room, don't put the boss room behind a puzzle.

DO Follow Principles of Good OSR Challenge Design

I wrote about this here.  For example, don't have solutions that require a specific class ability or specific spell.  

DO Encode Lore/Flavor/Story in Your Puzzles 

When possible, anyway.  It's nice when puzzles match the theme, tell a story, or reveal bits of setting lore.

It's also possible to have lore actual be the solution to the puzzle.  Like knowing that dwarves consider birds to be evil allows you to solve a puzzle but this only works if it's something that the players definitely remember--and never trust your players to remember anything.   They'll forget their names if you let them.  If you want to go ahead with lore-based solutions, best practice is to have the "birds are evil" thing 1 or 2 rooms earlier.

DO Use Multi-step Puzzles

Even if the first step is just looking around the room for clues.

It pads out the puzzle to make it feel more substantial (especially if it is an easy puzzle).  

Additionally, it allows you to feed the players clues one by one, instead of info-dumping everything on them as they enter the room.

DO Have an Alternative if Players Get Stuck

My favorite is to just let them smash it open.  They get the key, I get to dose them with the acidic gas that was inside the puzzle box.

Having a place to get hints also works.

The important part is to make sure that there's a cost.

MAYBE Have Extraneous Details

Players tend to get distracted by stuff.  They'll spend a lot of time discussing false paths and red herrings, even when you thought you did a good job creating a puzzle without any red herrings.

Like if you need to match the keys with the keyholes to solve the puzzle, an extraneous detail would be a cube covered in numbers.  Good chance that the players will spend too much time fucking with the cube and forget about matching keys entirely.

Having said that, puzzle rooms tend to feel pretty inorganic if every item in there is related to the puzzle.  And a lot of escape-room puzzles rely on the players finding the signal among the noise, so those puzzles definitely require extraneous details.

DO Consider an Overclue

Not just a theme, an overclue is a clue that applies to the whole dungeon.

A good example would be telling the players that each room is solved by one of the elements.  So if they had solved an air puzzle, a water puzzle, and a fire puzzle, they would then start searching the next puzzle for earth clues.  Maybe they would start digging in the dirt.  

Another good example is the riddle at the start of Tomb of Horrors.  The riddle contains about half a dozen clues about the upcoming rooms--the challenge then is just figuring out which room(s) the riddle is talking about.

DON'T Follow All the Rules Above

They're just guidelines.  Sometimes a puzzle is improved when you break one of the rules above.

Spiked Ball Trap
Skyrim Concept Art by Adam Adamawicz

Putting This Into Practice

I think my next Dungeon23 effort might be a dwarven puzzle-tomb.

The Overclue is the fact that the tomb tells you "this place is designed to be safe for dwarves, but to totally fuck up humans".  Players pay attention to that sort of thing.

(Sidenote: I don't usually allow players to start as dwarves.  I'm super not-fun like that.  This means that it will probably be a group of mostly-humans who has to navigate a bunch of puzzles that are "easy for dwarves")

Basic dwarf knowledge that will be explicitly told to the players when they enter this dungeon:

1. Dwarves are short, stout, and not very creative.
2. Dwarves value labor above all else.
3. Dwarves think that humans spend too much time thinking and not enough time working.

Using this overclue, I can then make rooms that are easy for dwarves, but horrible for humans.

"Easy for Dwarves" Puzzle 1

A hallway that reads "stand tall and be proud" but when you walk down it, horizontal blades swing high enough to avoid a dwarf, but low enough to decapitate a human.

I guess this is more of a trap than a puzzle, huh?

"Easy for Dwarves" Puzzle 2

A room that reads "humans will overthink this one, but it will be obvious to any dwarf".  The room is a long rectangle.  On one end of it is a stack of about 400 stone cubes, each one weighing about 100 lbs.  Each cube is covered with a different carving, showing a dwarf of a different profession.

Solution: just carry all of the stone cubes to the other side of the room.  The room is on a pivot, and once the weight has been shifted, the door opens.

Stop thinking; just do work.

Dwarven Racial Abilities as Part of the Overclue

I'll also remind the players of dwarven racial abilities.  This is also part of the overclue.

Racial Ability Puzzle 1

Dwarves have mild infravision, and can "see" the temperature of objects.

Puzzle: Different metals might look the same to a human, but look very different to a dwarf who passes a flame over them.

Human Solution: a human can just pass a flame over the metals and then touch them.  Even I can tell the difference between iron and aluminum if they've been plucked out of a fire.

Racial Ability Puzzle 2

Dwarves can tell if the ground is sloping, even slightly.

Puzzle: Find the low spot in this room.  Easy for a dwarf.

Human solution: pour water on the ground.  Spill marbles.

Racial Ability Puzzle 3

Dwarves can sense magnetism, including which direction is north.

Puzzle: Figure out which object is magnetic.

Human solution: It's still pretty easy to figure out which object is magnetic, unless it's too far away to touch iron to.  Hmm, maybe they don't know that they're looking for a magnet?

Some General Puzzles

Not every puzzle will be about dwarf lore, or dwarven racial abilities.  There will be some regular puzzles in there, too.

Example 1 - Find Numbers

A locked door requires the players to input a three digit number, then pull a lever.

The only clue is a painting:

A picture depicts dwarves bringing animals into the Underworld to save them before the Great Tornado destroyed everything on the surface.  A dwarf is leading a goat, a pig, and an elephant down the ramp, in that order.  A dozen birds of different types fly through the air, being stripped of their feathers by the righteous winds.  Further back, armed dwarves are turning away a band of disheveled, primitive humans.  Scattered on the field are a couple of cows, half a dozen pigs, a wolf, a goat, and a snail.

Solution: the animals on the ramp tell you what you are looking for.  Goat - Pig - Elephant.

Number of Goats: 2

Number of Pigs: 7

Number of Elephants: 1

The combination is 2-7-1

(I saw something very similar in an escape room once, except they had four paintings that each had a different number of seagulls in them.)

Example 2 - Audible Clue

A diorama, as tall as a man, revealing a cutaway view of Mt. Smaggaroth.  Inside are about a dozen mechanical toy dwarves.  When a wheel is turned, some of the dwarves move.  The miners will swing their pickaxes “tink! tink!”, the carpenters will swing their hammers “chop! chop!”, and the blacksmiths will swing their hammers “bam! bam!”  There are 10 of each.

After a little chorus of tink-chop-tink-chop-bam-bam-bam, a key falls out.

The key opens a panel that reveals a three digit tumbler input (like the previous example).

Above the first tumbler is the symbol of a hammer.

Above the second tumbler is the symbol of an axe.

Above the third tumbler is the symbol of a mining pick.

The solution is to remember the sound that the machine made. (You can turn the knob again if you need to hear it again.)

Hammers = bams = 3

Axes = chops = 2

Picks = tink = 2

The combination is 3-2-2.

Ghosts

I'm one of those people that thinks that ghosts shouldn't have stats.  Instead, ghosts are lingering bits of soulstuff, typically just a painful moment without context.  A ghost might materialize and go through some motions, but they are a type of recording, a recitation of misery.

They're meant to be interesting traps, where the players find success through cleverness, rather than rolling high with their most relevant skill.

by Luca Nemolato

How Ghosts Work

• Pouring holy water on an affected person can pause the effects of the ghost for 1d6 rounds.  Everyone knows this.  (This works on possession, too, if they succeed on a Save.)

• Ghosts can be laid to rest through some action, usually laying their corpses to rest, completing their unfinished business, or sanctifying an area.

• If you don't want to do all this sanctification business, you can destroy a ghost by breaking both femurs.  This instantly ends the haunting and puts a curse on the person who broke the bone.

• A cleric can also perform a funeral rite to appease the spirit.  This requires bathing the bones and singing to them.  It takes 2 hours.

If no trigger is listed, assume that the ghost triggers whenever you pass through the area.

By default, each ghost affects only a single person in the group; they get no Save.

The speak with dead spell can usually give you some big clues.  What does this ghost want more than anything else?  Ghosts are usually emotional wrecks, so it should be obvious.

So here are some ghosts:

The Fallen

Premonition

Vertigo.  An intense fear of heights.  Intense pain in your shins, wrists, and head.  Everyone is the group feels this.

Manifestation

No one is allowed to climb in this area.  Ropes will be cut.  Rocks will shift under your fingers.

Corpse

Half-buried in the rubble, a corpse with broken tibias, wrists, and a fractured skull.

Propitiation

Carry the skeleton out of this dismal hole.  Once the skeleton has been removed from the hole, the ghost is propitiated.  You can climb as long as you bring the skeleton with you.

The Starved

Premonition

Intense hunger.  You feel like you just lost 20 lbs.  You did just lose 20 lbs.

Manifestation

You must eat a ration every 10 minutes or fall unconscious.  10 minutes later, you will die from starvation, having lost over 100 lbs.

Corpse

Out of the many skeletons in this room, the skeleton with bite marks on its fingers.  (Ignore the other skeletons.)

Propitiation

An offering of food, placed direction inside the rib cage.  The ghost will be propitiated for as long as the food lasts.

The Drowned

Premonition

Walking alongside the water, you catch a glimpse of your own corpse under the water.  A moment later, it is gone.

Manifestation

You feel hands on your back as someone shoves you into the water.  From this point on, you cannot escape the water.  If you try to crawl back to dry land, the water rises up with, weighing you down and dragging you back in.  With great effort, you can get within an inch of the surface, but no further.

Your allies can breathe air into your lungs, or you can breathe through a tube.

Corpse

A skeleton, hidden in the muck.

Propitiation

Remove the skeleton from the drowning pool.

The Shackled

Premonition

You can feel cold metal around your ankles and wrists.  Whenever you take a step, you can feel a chain dragging behind your foot.

Manifestation

You cannot leave the room.  Your wrists and ankles cannot cross the threshold of the doors.

Corpse

There are many corpses in this room, some still shackled, some scattered across the floor.

Propitiation

You must destroy all of the shackles.  There are 4 sets in this room.  Bashing them out of the wall (or breaking the links with a hammer) will incur 4 wandering monster checks.  If you have a crowbar, you can do it more easily and quietly, and will only incur 2 wandering monster checks.  Either way, it takes two hours of work.

The Betrayed

Premonition

Your companions are looking at you when they think you aren't looking.  You can hear snatches of whispers.  You suspect they are plotting against you.

Manifestation

You flee from your companions.  After 3 rounds, you can save every 1 round to end this effect.  When you recover, you can remember being stabbed between the shoulderblades by a green-jeweled dagger.  The ghost will manifest again in 1 hour until you leave the dungeon, or the ghost is propitiated.

Corpse

A shriveled corpse with dagger wounds in its back.

Propitiation

Destroy the skeleton of the Betrayer.  Alternatively, destroy the green-jeweled dagger and return the corpse's coin purse.

The Betrayer

Premonition

White-hot greed, so powerful it feels sexual.  You can't stop looking at the valuables your companions have.

Manifestation

Whenever new treasure is available, you will insist that it is yours.  If your allies force you to give it up or share, or refuse to let you carry it, you will pretend to agree, then grab the item and attempt to flee out of the entire dungeon.

Corpse

A shriveled corpse with two coin purses and a green-jeweled dagger.

Propitiation

Destroy the skeleton of the Betrayer. 

The Sacrificed

Premonition

You hear the chanting of the cult.  You feel the heat of ancient torches.  Your shirt is ripped open, and you can the feel the tip of a dagger resting on the skin over your heart.

Manifestation

Everyone hears the chanting now, repeated endlessly "The lord demands a gift".  You are stunned, and your chest is bared.  Everyone can see the deepening wound on your chest.  In 2 rounds, you will die.  "The lord demands a gift."

You can flee from the room, but you'll drop to 0 HP, the ghost will trigger the next time you enter the room, and you'll never have enough time to pry the gems out of the idol.

Corpse

A skeleton on an altar.

Propitiation

Sacrifice someone else on the altar.  Alternatively, sacrifice a valuable possession on the altar.

The Abandoned

Premonition

Your leg becomes stuck.  You call out for help, but all you see is receding torch light.  Your allies have abandoned you here.

Manifestation

You will become a useless ball of terror unless someone is holding your hand.

Corpse

The shriveled corpse of a woman, hidden in the gloom of a pit trap.

Propitiation

As long as you bring the skeleton with you, she will not harm you.  You must treat her like one of the party, though.  If you forget to introduce her, the sense of terror will begin to return.  She takes up 3 inventory slots.

The Eaten
by Dunkey Halton

Premonition

You feel a fat predator tongue scraping against you skin.  You feel a mouth sucking the marrow from your bones.

Manifestation

You must run and hide, squeezing into the first small space you can find, and squeezing in as deep as you can.

Corpse

A cracked mass of human remains inside the belly of a nearby predator.

Propitiation

You must roughly reassemble the skeleton and rebury it.

Some Traps

Chris wrote up a list of some traps that don't suck.  I'm going to write some more, since that seems like a good thing to make a list of.

What makes a good trap?  

It should follow good OSR principles (similar to the obstacles post I wrote way back).

• No obvious solution.
• Multiple possible solutions.
• Solution depends on common sense (rather than system mastery).
• No specific tool required (no McGuffin, no singular spell, etc).

What is a trap?

A trap can be obvious, such as an open pit.  With obvious traps, the puzzle becomes how to best get across the trap.  Traps don't have to be difficult.  Easy traps can be fun, too.  AND easy traps can become weapons that you later use against monsters in the dungeon.

Obvious traps are probably the hardest to write, and the most fun.  They kind of blur the line between obstacle, puzzle, and trap.  An obvious trap needs to have (a) a reason to engage, (b) a visible mechanism, and optionally (c) an explicit risk.

A trap can be surprising, like a subtle pressure plate.  With subtle traps (where the PC is likely to stumble into it) make sure that you give the player a chance to react before the trap goes off.  We want to give the players interesting choices to make, not just tax their HP.

A boulder rolling towards you is good.  You still have options.  Compared to. . .

A subtle pit trap in a random location sucks.  It sucks because the "solution" to them is to spend your time tapping on the floor with a pole, or pouring out water and seeing if it seeps between the stones.  (I know there is a whole branch of old-school play that enjoys this style of play, but it's never appealed to me, since I believe that there are more interesting ways to challenge players.)

Where should subtle traps be hidden?

Please don't hide them willy-nilly.  Putting a pit trap in the middle of a well-traveled corridor threatens verisimilitude (since aren't orc patrols passing over it every thirty minutes?)

Place traps in logical places.  A kitchen cabinet is probably not going to be trapped, but the chest in the shaman's room probably is.  

If you are going to hide damaging traps, try to build up to them.  Telegraph the possibility before the traps appear.  Before you have complicated double pit traps and slides, it's good to have a room with a small pit trap (to inform players that hidden pit traps exist here).  Or better yet, a room with a broken (exposed) pit trap.

You don't have to telegraph the danger, just the mechanism.  

For example: a lever might open a hole in the ceiling, dumping spiders down onto whoever is below.  A smart party will pull the lever with a rope lasso from 20' away.

This is a good trap.  A player who dies from spider bites will (hopefully) sigh and say "I guess I deserved that.".  

That's what you want from a trap.

Some Traps

Not all of these are technically traps.  Some are just interesting dungeon features.

Horrible Hallways

1. Wall of fire.
2. Zone of unconsciousness.
3. Climb a diagonal shaft, rotating.
4. Crush hallway.  Find a way to survive the crush, or at least move really, really quickly.
5. Portcullis that slams shut to split the party.  You can reunite 1-2 rooms away (don't split the party for too long).
6. Obvious pit trap.  The correct path is hidden at the bottom of the pit.
7. Insanely hot hallway (or room where you have to perform some activity).  Anyone trying to sprint through it unprotected is probably going to burn their feet and die.  Things that reduce damage: being soaking wet, air circulation, walking/standing on soggy leather.
8. Subtle pressure plate.  The trap triggers when weight is taken off the plate.
9. As above, except there are several pressure plates in a row.
10. Goblin barricade staffed by several bow-wielding goblins.

Wretched Rooms

1. Obvious trigger: taking the sword off the pedestal.  Two copper spears shoot out of the wall, impaling an incautious explorer.  A round later, lightning begins to arc between the spears.  A round later, the room begins to fill with water.
2. Poisonous gas seeps from a crack in the wall.
3. Lake of acid.  Get to the island.
4. A dripping wet door.  Opening it floods the room with ancient, rancid water and 3 zombie sharks.
5. Lock that can only be opened at a certain minute each day.  Adjacent, a lock that can only be opened at a certain minute each week.  Adjacent, a lock that can only be opened at a certain minute each year.
6. Archway.  Anyone who passes through it is transposed with a ghoul in a nearby room.
7. Climb a frictionless wall.  (Have fun collecting large furniture.  Shitty tables are treasure now.)
8. The floor of this room is laminated with symbols of disintegration.  If a symbol is touched, all non-stone material in the room will take 3d6 Con damage each turn.  In the room, an (unsupported) pedestal with a stone McGuffin on top.  In the ceiling: spiders and spiderwebs.
9. Everything appears distorted in the mirror.  Humans appear to be orcs, swords appear to be hammers, etc.  The trick is to notice that the pen appears to be a key, and the mouse skull appears to be lock.  Inserting one into the other will cause the door to open.
10. Huge wooden bowl, lined with thin, insoluble gold foil.  Filled with horrible, fuming acid.

Obnoxious obstacles

1. The magic stein can only be carried by someone who is colossally, totally drunk.  They have to carry themselves--no one else can help them.
2. Carry a baby out of the dungeon.  No, carry ten babies.
3. When the lid of the sarcophagus is placed back on top, the bottom of the sarcophagus opens.
4. Sign says "teleporter" but it's really just a big blender.
5. The dragon is sleeping!  Steal things quietly.  (Common sense: it's quieter to carry a chest away than it is to open it, a sack of coins is guaranteed to clink, etc).
6. As above, except some goblins just showed up.  They want to kill you quietly, but if the dragon wakes up, you're all probably going to die.
7. Crossing an underwater lagoon.  Hope you brought a canoe.  Of course something attacks during the crossing.  A fast boat can escape it, a floating table is easily capsized.
8. Functional teleport brings organic material to one place, and inorganic material to another.  Allow teleported people to communicate this (possibly by shouting, roll for random encounter) so they can make a more informed decision.  An incipient threat hastens plans.
9. The door can only be opened in your dreams.  If you open it in your dreams, you can pass through it in real life.  While your body sleeps on the altar, it is inhabited by the spirit of an ancient wizard.
10. Before you can run through them, you need to observe the swinging pendulums to determine their pattern.  Anyone observing the pendulums is hypnotized by them, staggers safely through them, and begins to self-mutilate by dancing in the middle of all of them (1d3 damage per turn).

d14 Trapped Chests

Trapped chests.  A classic feature of the dungeon, and yet one that is often as much fun as spilling a box of cereal.

I'm writing this post under the assumption that you're running an OSR game, and that there is no Perception or Disable Device skill or whatever.  All traps and shit like that is done with the old-fashioned "I like under the rug." "You find a trap door." method.

(Digression: Finding and disabling traps is a goddamn dungeon staple.  It's bread and butter.  And yet Perception + Disable Device is the shittiest fun way to handle it, because you're just throwing those skills at problems like a robot.  It becomes a test of the character sheet, rather than the player.)

First warning: before you start throwing trapped chests at your players, make sure that they know that trapped chests are a possibility in this place.  You can warn implicitly, by throwing some gently-trapped doors at them early on, or showing the corpses of people killed by trapped chests, or explicitly, just by telling them "You heard that dwarves often trapped their funereal chests."

Second warning: no pixel-bitching.  Having players exhaustively search every chest they find is exhausting.  No surprise there.  Make the clues obvious.  Make the solution obvious.  And by obvious clues I mean "give them the information they need easily".  And by obvious solutions I mean "solutions should be apparent that they are solutions."  (Especially with traps, which sometimes carry big costs for failure.)

Shark Fact: traps don't have to be hard.  They don't have to kill players.  They can (and should) but a trapped chest can be an enjoyable experience even if it doesn't fuck people up.  It's okay for a trap to simply be an interesting feature, or an interesting decision.  

1. Skeleton slumped out in the hallway.  Needle sticking out of the keyhole.  Covered with some blackish grease.  (This is poison.)  Chest cannot be opened until the needle is pushed back into the keyhole and the trap reset.  A player with a shield or gauntlet could easily push it back into the keyhole.  The poison needle could also be broken off; this yields a useful poison needle, but makes it awfully hard to unlock the chest (since you have to push the mechanism back into place).

Shark Fact: This first trapped chest is pretty harmless, but it's interesting.  An accurate investigation of it (or a successful Disable Device check) will yield the information about how it works, but the players still have to decide for themselves if they want to break off the needle or push it back in.

2. In a room with a metal floor, a stone plinth holds a copper chest.  The chest is electified, of course.  Just knock it off the plinth with a quarterstaff.  (Live wires run up through the center of the plinth.)

Shark Fact: Chests often contain fragile things like potions, scrolls, and art objects!  Each of these has a 50% chance of breaking if the chest is smashed open or dropped!  Yay!

3. There is a chest on a plinth.  A pressure plate beneath the chest is triggered when the chest is picked up, or if it is lightened.  The trap can be thwarted by putting items in the chest of an equal weight.  Anyone who starts picking up the chest or emptying out its contents will hear the mechanism start to click beneath the chest, and will have a chance to put the put it back down.

Shark Fact: Give your players the benefit of the doubt.  Unless they tell you otherwise, always assume that they are doing it carefully, slowly, and observantly.  (If you are using the old rules where it takes a 10-minute adventuring turn to do anything at all--this is why.)

4. After opening the chest an inch, a tripwire is visible on the inside.  If the chest is opened more than an inch, the wire is tripped and the vial of flesh-eating gas inside the chest is broken.  (This isn't really a trap, it's more like a second treasure.  What's the chest going to contain that's cooler than a pre-made flesh-eating gas bomb?)

Shark Fact: Even though you are giving your players the benefit of the doubt, there's still going to be some idiot who announces "I'm going to open the chest as fast as I can while standing behind it!" or "I'm going to throw it down the stairs!" so don't be too sad; your flesh-eating gas will probably still get to kill someone, even though that isn't its primary purpose.

5. Chest is full of bee golems.  Or just one big bee golem.  It buzzes angrily when you shake the box.  And if you open the chest, you can shut the door in time if you win initiative.

6. Chest is part of a support pillar.  Smashing the chest will collapse the pillar, and bring down the whole ceiling.  Attempting to pick the lock and failing will have the same result.  There's a key later in the dungeon, but players are pretty much guaranteed to be hasty and fuck it up anyway.

7.  Chest is covered in green slime.  Chest is made out of a highly explosive ceramic.  (You might want to preface this one with evidence of exploded chests, or even better small containers made of explosive ceramic.)

8. Chest stinks of chemicals.  It is full of acid.  All of the treasure is metal.

9. Chest is a chest of non-detection.  Always appears empty.  Actually contains gems and shit.  (Alternatively, contains a ghoul assassin taking advantage of the chests effects.)

10. Chest of contrariness.  Chest has a tinted glass window that allows you to see it's contents.  When the chest is open, the contents become locked in a force field.  The chest is solved by just leaving it closed and then reaching through the (now intangible) window.

11. Chest is only visible in a mirror.  To open it, you must insert the key into the keyhole (by watching yourself in the mirror).  The chest is silver and awesome looking.  There is also a fake chest in the room, covered in blood and spikes.  Inserting the key into the false chest causes it to shooting out ninja stars.

12.  Chest is chained to the wall.  Beside the chest is a bloodstained butcher board, complete with a cleaver.  (The chest is actually a mimic.  If you feed it some tasty meat before you approach it, it will let you take items out of it.  It'll probably purr while you do it, too.

13. Wall of gripping metal hands.  Hands will only allow you to take an item if you give them an item of the same time.  For example, they won't release the magic sword until you give them a different sword (of any time).  There is at least one item that is difficult to replace (like what do you have to give them in order for them to release the creepy doll)?

14. Chests with particular opening conditions.  The blue chest covered in painted fish can only be opened underwater.  The chest depicting witches flying over a clock can only be opened at the witching hour (between 3 and 4 am).  The chest covered in painted birds only opens at the touch of a bird.  (You can invent a million of these, I bet.)

Three Types of Green Slime (and Three Types of Traps)

So, I was writing up some rules for green slime earlier, and I was wondering what to write.  Is green slime something that is noticed with a Wisdom roll?  Is it noticed when the player specifically looks at the location where the green slime is hiding?  Or is it out in the open all of the time?

It's a tricky question, but only because I was making it tricky by trying to bake it into the description for green slime.

The reality is that green slime is not really a monster.  It's a trap, or part of a trap.

And when a DM plops some green slime down on the map, they should be able to use green slime however it best fits their ideas for encounter design, depending on what kind of slime it is.

Here are three kinds of slime.

The first kind of slime is always out in the open.  Players always notice it.

You can see it covering the entire ceiling of the hallway, ready to drip down onto anything that walks below it.

With this kind of slime, the question is "how do we get past this hallway full of green slime?"  That's what is tested.

The players must think of creative solutions to this problem.  Rolling a wheel of cheese perhaps?  Taking cover under a tower shield and simply running for it?  

It's an interesting problem, and one that leads to creative problem solving. Good job, slime.

The second kind of slime requires players to look in a specific spot.  If the players don't look in the right spot, they won't spot the slime.  

With this kind of slime, the question is "how do we search our environment to avoid traps?" and that is what is tested.

If you fail at searching your environment carefully before advancing, you get a face full of slime as punishment for being bad at the game.  Do you hear viscous dripping behind the door?  Is the bottom of the fountain thick with green growth?  Do you try to illuminate more of the mine shaft before you climb up it?  

Also an interesting problem, and one that leads to thoughtful exploration.  Good job, slime.

The third kind of slime will only be noticed by players if they roll well.  Perhaps it is as random as a coin flip.

With this kind of slime, there is no initial question.  You're gonna get slime on you, or you're not, and your choices have no effect on whether or not you get green slime on you or not.

So, you're gonna get slimed, and there's nothing you can do about it.  The question becomes, "what do you do when you get slimed?" which is more interesting when there are multiple things going on at once, so you are forced to divert your attention between the slime and the other thing.

That's an interesting problem, and one that leads to tense moments.  Good job, slime.

It's a brutal mechanic, that's for sure.  But so are petrification and level drain, so there is precedent for brutal mechanics.  I have a monster that spits green slime, which is a little more interesting, because then players have to choose between cleaning the slime off or dealing with this tubular cassowary.  And since the players can learn of it's slime-spitting tendencies and perhaps get it to blow it's load onto a tower shield or something.

The fourth kind of slime is the bad kind of slime.  It's the kind of slime that falls on you as soon as you walk into the dungeon and eats your armor.

You had no agency.  You had no chance to detect it or bypass it.  It's just a tax that is levied on you as you progress down the corridor.  A shitty toll that you must pay in order to proceed.

It's the same if there is a Perception roll.  Either you make your roll and avoid it, or you fail your roll and take damage.  Again, there is no agency, no interesting choices to be made.

This is bad.  Don't do it.

The Straw Man Speaks

SM: Hey, I thought of some situations that fall into multiple categories.

AK: Yes.

SM: You know, you could extrapolate this to all traps.

AK: Yes.

SM: So which one of these should I write down when I'm writing my Monster Manual entry on green slime.  Which is the best kind of green slime?

AK: You haven't been paying attention.  Don't write down any method of "how to spot green slime".  You're only limiting its usage, and that's not the interesting part of green slime, anyway.  The whole point of writing things down is to give us a hard copy to refer to, usually in shorthand.  This gives you freedom to write up green slime traps however you want, which all have the same penalty for failure: you get green slime on you.

• Use obvious slime if the puzzle is "how do we get past it?".
• Use findable slime if the puzzle is "how do we search this environment for dangers?"
• And use luck-based/automatic slime if the puzzle is "how do we handle getting slimed?" and you are kind of a dick.