Traps, Hazards and Terrain: Hacking

Been Gone

We’ve been awfully quiet here at Rules as Unwritten since Fingolfin and I have been working late, distracted by DndNext and actually trying out new things in side games. That part in the middle, about the new slated edition, is one that’s probably been most of the cause for slowing down the content here. You see, we love 4e. Of course we see many things worth reexamining and course-correcting, we can’t help but be a little bummed.

But I’m over it now (a bit), because 4e is still alive and kicking, at least for me—and 5th edition will be a really great evolution I hope. I play in a weekly game, I run a bi-monthly game out of state, and I’ve even been able to sneak in a few Saturday games that have become little testing grounds to help me solidify my thoughts about what works and doesn’t work in the great game we love.

That said, we hope to bring you more content soon, but sometimes it’s hard to invest time and energy in project pieces that you now know could be irrelevant in the near future. But it’s not so terribly near that we should throw in the towel, so here’s a bit of crunch from the last game I ran that I found interesting.


Have you ever played Bioshock? This is a fantastic game, and although I think I mentioned it before when I played the first game in the series last year, I just recently picked up the sequel, and lo, it is just as good as the first in terms of game play. I have many reasons to remark on why it is such a great game (story, graphics, etc), but the relevant reason in this post is the way the game deals with traps. In the post-distopian submerged world of Rapture they built security systems to protect portions of the city in which you traverse. Since things went haywire down there, you end up facing these little bots and thwarting them is the challenge. The “treasure” that you collect is usually guarded by these machines, and the security usually translates into mini-games, which when solved open the “chest” and reward you, or when failed, bring on a wrath of machines that can slap your wrist pretty nasty.

The mini-game is just a little meter that shows up on your screen with an oscillating needle—you’re intent is to land the needle in a row of the safe areas and to avoid the danger zones that will result in a failure. This can get complex and stressful when there are baddies around shooting at you (thus part of the fun). However, the game introduces an additional level to the hack that makes it even more fun: the ability to turn the trap to your side.

Either by landing the needle in an even smaller special zone in the meter, or by collecting “auto-hack darts” and catching these little buggers with them, you can make these robots your slaves. This sets you up for some interesting situations where you can lure your enemies into zones with your allied devices, and not spend a single bullet of your own to put them down.

Stealing Their Idea

I liked the idea enough to translate it into D&D. One of my gripes with traps is that they are often ignored in combat because of their relative insignificance. I’ve always felt that their danger (either damage or control) should be considered much higher than a normal monster for the shear fact that most do not move at all, and a lot of them can be shut down with a single skill check, thus resulting in the PCs practically ignoring them. For a little twist, consider a trap like the Amber Eye to encourage more engagement with the trap. The trap itself has a means to not only shut down the constant threat it presents on the battlefield, but offers an opportunity to change it into an advantage.

Amber Eye

The Amber Eye trap is a tiny object with a coloration on one part of its surface in the likeness of an iris and pupil. After its owner spends 10 minutes programming what it should detect as enemies, the Amber Eye levitates in place at eye level as a vigilant sentry. When an enemy to the Amber Eye moves within 8 squares, it rolls for initiative and begins to pulse, potentially catching the enemy in its Burning Eye. Though an Amber Eye may seem like a perfect security device because of its longevity and devastating power, its weakness is in its ability to be tricked by others into reprogramming, potentially turning it from a trap into a piece of artillery for interlopers.

While playing Bioshock I thought of that little meter mini-game and felt it could easily be translated into a move action, allowing for a player to focus on the trap with a sacrifice of downgrading a standard action, or to pick at it round by round. The best way to turn the device against the PC’s own enemies is to not miss one of those thievery checks. However, the trap could potentially be distracted as well, if you want to remain in its reach but not get shot at. Hopefully I was able to bring in something new to the trap mechanic, while still providing the good old circumvention methods of either bashing it to bits, or sneaking around it entirely. Enjoy!


Traps, Hazards and Terrain: Complexity

Keep it Hidden

One of the things that makes a trap a trap, and not just a hazard, special terrain or just an avoidable mechanism is the fact that it is hidden. Hidden, however, can mean a lot of different things, and although one might consider something like quicksand to be terrain or a hazard just because it is physically made of earth, I would venture to say that the entire purpose of it being different from normal sand is that you didn’t know it was quicksand when you stepped into it. Thereby, trapping you.

The concept of being hidden is something I’ve had to embrace when designing traps since 4e came out because traps aren’t really considered important (read: fun) outside of combat any longer. A trap on a door that sprays acid on the unlucky PC with the thief’s tools is no longer considered as integral to the game as it used to be. There’s probably a good reason for that, that’s a topic for another post, but it’s clear that traps within the context of combat encounters are where they are most integrated with the game in 4e. They can make a battle more challenging without the expected addition of even more monsters, but they can also add a twist or unique setting to an otherwise dull environment.

That twist always boils down to a trap being, in some way, hidden on the playing field. But the pressure plate that triggers a barrage of poisonous needles is a little bland for you more seasoned players out there. You DMs can make the DCs as high as you want, and sure, catch the PCs every now and then with your futile volley of venom, but in the end, it’s a little boring. It can surely be appreciated as old school, but we’ve got to come up with some new material.

Add a Dash of Something Unexpected

To make this new material, or to spruce up the material that we already have, we need to add a dash of complexity to our devious mechanisms. Especially at higher levels it becomes difficult to believe that powerful and magical creatures like mind flayers, githyanki, rakshasas and efreeti are using simple flame jets and rolling boulders. The complexity of a trap can be the veil, the trigger and the capture, while also continuing to challenge the PCs during the course of an entire combat. The key to designing these kinds of traps however is to make them a bit more screened from your players, but easy for you to adjudicate.

Complexity doesn’t need to mean that it is more complicated however! Complexity to a trap just means that an added element to a mechanism can throw off even a wary PC for one or two rounds longer, providing a little extra mischief and hopefully a little extra fun.

A Few Tips for Sprucing Up Your Traps

  • Don’t hide your traps, disguise your traps: Got a tripwire trap that you want to use? Bring a little danger into the mix by filling a room full of tripwires. Only you know which squares are the trapped ones.
  • Anticipation of danger is worse than danger itself: You put a hidden boulder hanging from a chain in the center of a room that the PCs must pass through, and the fun is they might get crushed. But put four clearly visible boulders hanging from chains in that same room and indicate that some of them might be trapped, and you’ve got even more fun watching the PCs waiting to be crushed.
  • Go for the “I don’t get it” response: There’s a beginning, middle and end to every trap, just like a good story. The PCs see the bait, they experience the switch, they escape danger. With a little complexity you can intensify each of those steps. If you’ve got a metal claw trap on a pedestal with a clear range of danger, place a magical gold ring hovering just out of that claw trap’s range and wait for the response. (silly PCs, the RING is the trap!)
  • Red herrings: Normally red herrings in the plot of your D&D campaign is not advised because PCs make their own false leads and yours gums up the flow. The trap is a short story however and you can get away with these here. “There’s clearly a pit trap in the middle of the room…but why are the walls painted red?” No reason, just an evil wizard messing with them. Let them wonder, that’s half the fun.
  • Better yet, separate the clues: If the red herring idea still gums up your player’s reactions, consider placing dungeon/adventure clues alongside your traps. The tree stump has 12 stacks of 4 platinum pieces each upon it, and the rogue detects a thin wire running underneath some of the coins. What the players don’t know is that all the coins are trapped, they’re just piled up that way because the redcap owners are superstitious about keeping their treasure in odd quantities. (Don’t be afraid to accept an Arcana or History check from a character to determine what’s going on with the stacks, remember to reward them for ferreting out the clues.)
  • Don’t be stingy and don’t hold back: Don’t just use a poison dart trap in that hall, use another trap on top of that one that causes poison vulnerability. It’s one thing to be trapped in a garbage compactor with a dianoga lurking around your feet, but it’s another thing when the walls start compressing in.

New Traps

These two suckers are a bit more complex than you’ll find in any Essentials guidebook, but in my opinion that’s what gives them appeal. The traps written in a lot of the core guides are simple, true, and although they may be easier to use, they just play out like obstacles. There’s a difference between obstacles and an obstacle course. That difference is fun, and only a little sliver of complexity can make the distinction.

Dragging Statues
Hags, medusas, fey and aberrant creatures can make good use of this trap for their lairs. After carving, buying, or petrifying creatures into statues, a bit of enchantment on a few in the area can delay and harass intruders even to the point of death. In any case, they’re disoriented, separated, and ready for the lair’s guardians when they arrive. Don’t be afraid to place the four allotted statues amongst four other statues in a lair (using one of the tips above) to further add the excitement of anticipation to this trap.

Opportune Ring
It’s a trap, it’s a magic item, it’s a cursed magic Item! With all the new material out for Mordenkainen’s Magnificent Emporium, curses and cursed items have been a hot topic. Though I’m itching to give these new items a critical review, I was inspired to mix things up a bit in trap design by baiting players with boons while they are adventuring. An extra action point is nice little prospect, but a group that can’t reach the extra level of knowledge might fall quickly into the ring’s trap. In this different kind of instance, you can even put in a little extra risk in the trap that continues on throughout the day, and even days after.

I hope you’ll test these traps out and enjoy the extra level of complexity that makes them something your players will enjoy rather than furrow their brows. We’d love to hear any reaction to this bundle of crunch, so chime in if you’d like.

Traps, Hazards and Terrain: Detection

Why call it a trap if you know where it is and what it does? If a player knows the location of a dangerous area, they will simply avoid it. Sure you could place traps precariously around a limited area, but what this does is basically communicate to the players that they simply shouldn’t move in those spaces. That’s not a trap, that’s a hazard. What’s the difference between moving into a trap’s area that can deal 2d10 damage and knock you prone and falling off of a 20 foot ledge? Not much. At least, not enough.

As I asserted in the last installment of this series all about traps, hazards and terrain, a trap should be defined by 4 things, one of which is the quality of being hidden. We have a system in this game for uncovering hidden things, and that’s called Perception. Although I feel like the passive Perception feature in 4e is a nice evolution from days of yore when there were constant Search, Spot and Listen checks, I’m not convinced it should be entirely used for detecting the placement of traps. Now before you cock an eyebrow knowing that passive Perception was developed primarily for this purpose in the first place, my argument is that it seems a trap’s entire area of effect is effectively revealed if a character in the group has a high Perception. I want that player to be rewarded for their choice to excel at Perception, but I also don’t want all the tricks out of the bag as soon as they walk in the door and combat begins. What’s the point of designing traps at that point, if you immediately reveal them when the characters gain line of sight?

I realize there are ways to manipulate this: 1/ use blocking terrain 2/ use a higher level trap, and therefore a higher detection DC 3/ just reveal what the character actually senses, not necessarily the trap’s area, etc. I’m not satisfied with these answers though. The third one however is the one that is getting closer to what I’m after. In the original Dungeon Master’s Guide traps often had multiple Perception detection DCs, revealing indications of a trap’s presence to different levels of skill. But let’s be honest, if the DM notes there are a set of holes in the ceiling above this particular set of squares, you know something fishy is there, dangerous area equals hazard, and we’re right back where we began. Again, I realize you can place the trigger in an area not directly under those holes, and that’s a nice little trick, but honestly, that requires tailoring for each encounter. I can do that on my own as well, but what I’m looking for is a system, something that works across all traps employing subterfuge.

Another thing that irks me about a simple passive Perception score revealing the location of traps on a battlefield is that with one character investing in the skill, the entire party is privy to the absolute areas of danger. I find this breaks verisimilitude and makes designing traps a waste of time. And let’s face it, because Perception is Wisdom based, a useful skill and on a lot of classes’ skill list, there’s a good chance you’ll have a good spotter in the group. And if you don’t and you’re using a lot of traps against them, shame on you for exploiting their weaknesses. I’d rather have a rule set that caters to any kind of group and rewards individual and cooperative work to overcome obstacles.

To do this I have designed a simple two-tier system of detection that works in conjunction with the rules already outlined in the source books. These rules beef up the concealment and surprise quality of traps and are about as simple and streamlined as I can make them. Here’s how it works:

Traps employing concealment have two traits: a vicinity square and an area:

Vicinity Square:

A vicinity square is a single square that indicates the surrounding or nearby location of a hidden trap. If a player beats a trap’s Detection DC with their passive Perception score, the vicinity square of the trap is revealed to them. If a player beats a traps’s Detection DC with their passive Perception by 5 or more, then the entire trap’s area is revealed to the player and the player can make an appropriate knowledge check to determine the effects of the trap.


The area of a trap can be in any shape or form, but is commonly a burst with its vicinity square at the center of the burst. The more dangerous the trap, the larger the burst or more elaborate the area is. When a creature enters the area of a trap they must make a Perception check to avoid the triggering attack. If they fail the Perception check, the trap triggers. If they succeed on their Perception check, they can move through the trap’s area without triggering it until the start of their next turn.

These rules accomplish several things:

  • Traps have the potential to surprise an adventuring party, even if the vicinity of a trap is known.
  • Players who have invested in Perception can help reveal the vicinity of traps on a battlefield.
  • Players who have invested in Perception are still more capable at avoiding traps altogether.
  • Tactics for raising the level of traps to make them more difficult to detect, as well as indicating only specific qualities of a trap to retain its intrigue still apply.
  • Characters can have no knowledge, a small notion, or full disclosure to the presence of traps on the battlefield.

llustration of the system:

One might say that this decreases the likelihood of a trap’s effect occurring, as now not only is there an attack roll, but a successful Perception check moving into the area negates any attack at all. I would pose however that this opens traps up to a more broad range of danger; you could design them to make an attack and have the Perception check for entering the area as above, or you could have the triggering attack simply have an effect of damage or imposing a condition without any attack at all. Moving into the area should be dangerous and unexpected, but spry and intuitive characters should have a decent chance of negating the effects.

Note a few things as well: 1/ When the Perception check is failed for entering the area, the entire trap triggers. This may have many forms as individualized by the trap, but typically it would attack everything within its area. This could be a deliberate choice by a character or monster to use the trap to their advantage. 2/ A trap’s area can be any manner of shape on the field, but should generally adhere to bursts, blasts and walls. If the area of a trap is still unknown, anticipation and fright can ensue. See the different arrays of vicinity squares and areas illustrated below.

Finally, I’ve provided another little trap that uses these rules so you can see it in action. The trap simply has its area and vicinity square described in the section under Traits. The Perception mechanic is reinforced under the trigger and the rest is basically set up like any other monster. I hope you can take these ideas and weave them into your own game. Until next time when I hope to take traps even a little further by exploring different ways traps can be hidden!