Home Articles DnD Trap Tuesdays

DnD Trap Tuesdays

by MTDadmin
DnD Trap Tuesdays

DnD Trap Ideas, Every Tuesday!

Welcome to DnD Trap Tuesdays. Each Tuesday we’ll be releasing a new article focusing on a trap that you can easily implement in your DnD games. These articles are going to cover all sorts of traps, their types, their uses, and why you would use them for your game. Not all traps will be elaborate, but every trap will have scenarios and purposes where they can be used effectively to make your games more fun. So let’s dive right in with our first installment of DnD Trap Tuesdays talking about triggers.

Setting Off Traps

Dungeons and Dragons traps can be set off in a lot of different ways. When most people think of traps they think of the basic mechanical triggers for them. They think pressure plates, trip wires, buttons, and levers. While these are all valid ways to set off a trap, they are the tip of the iceberg when it comes to trap design!

So what are the triggers that can set off a trap, as far as DnD trap rules go? Based on The Dungeon Master’s Guide, traps have the following activation types: Location, Proximity, Sound, Visual, Touch, Timed, and Spell. These are all very generic, but each one has a very specific way in which they are activated. It’s important to think about each of these as it applies to rules because giving a clear description of how a trap is set up and set off is important for your players. If your players don’t understand the mechanisms of the trap and how it was set off, they likely won’t find it very fun.

Trap Triggers By Type


Location Trigger

A location trap is set off when someone stands in a particular spot. This could be a stone pressure plate as easily as it could be a magical rune on the floor. The type of mechanism can be described in many different ways, but the important thing to get across to your players is that by being where they are, they have triggered the trap. When using location traps, it’s good to make sure the description for each indicates the specificity of the location. A magical sensor might trigger for an entire room, while a pressure plate might trigger for a specific square. Indicating this to your players will help them spot more traps in the future.

Proximity Trigger

Proximity is different from location in a very important way. Proximity traps are set off based on distance, not on the square that someone is in. While the distinction may seem small at first, a proximity trap is much easier to set off than a location trap. Let’s say you have two of the same trap that differ only in the trigger, one based on location to a treasure chest and the other based on proximity. The location trap will have a mechanism that can be circumvented by angle of approach, such as opening the chest from behind. In contrast, the proximity trap would trigger from any direction so long as the players come within a certain radius.

Most often proximity traps are spell based, with spells like Alarm. This makes spotting and disarming this trap innately different than mechanical ones. It’s also a great opportunity to let your spellcasters detect and disarm traps that your rouges might not be as good at.

Sound Trigger

Sound triggered traps are often neglected in DnD games. They seem like could get a lot of use, but many DMs never encounter good examples of these and have little information to design their own. Magical sound triggers are the only ones that the DMG talks about, but really there can be mechanical and monster triggered sound traps as well. The magical sound traps function similarly to Alarm: if the players make too much noise, fail a stealth check, or talk near the trap, it goes off magically. For a mechanical sound trap, you can set up avalanches or cave-in traps. Lastly, monster lookouts can be used as the trigger to a trap. We see a good example of this early in the Dungeons and Dragons Starter Set where a goblin lookout can hear the party and trigger a flood trap early on in the game. This is a brilliant way to make a trigger for a trap be unexpected and adaptive with different ways for your players to overcome the challenge.

Visual Trigger

A visual trap trigger again is often magical. Usually they are akin to Arcane Eye, Clairvoyance, or True Seeing. These can also be set off by lookouts, and the option should be considered based on your design for a trap. An interesting note here is that if a visual trap would have line of sight, it can be circumvented with darkness unless the trap also has a Darkvision spell on it. This allows you to build a visually triggered trap that can be a fun puzzle where your players need to hide in dark spaces to avoid the arcane eye.

Visual triggers are very similar to proximity traps, but they typically have a line of sight component. Very rarely would you want to use a visual trigger with a 360 degree line of sight. For this trap it is best to ensure that the line of sight is directional and obvious. An example would be a stone eye that changes direction over time, or a gem that faces a particular direction. These clue players into the mechanism of the trap while still giving them something challenging to work around.

Touch Trigger

Touch is the trigger that most people are familiar with and it is the easiest kind of trap to put together. These are your typical snares, tripwires, and alarm spells. Touch traps should be made clear to people using theming (making it understandable by using environmental and story clues) but by no means need to be. It’s more fun if your players can see a trap and start to learn the patterns from them for the future than to have them each activate differently or be invisible. Touch traps are most often avoided by not touching the items in question or by using perception and dexterity checks to observe and move around them. While very simple, these traps are effective and common.

Timed Trigger

Nothing adds more tension to a scene than a timed trap. These are great because you can hint at them in a lot ways and show players how they work. Timed traps could be floor spikes that come up periodically, or a ceiling trap that descends at a certain rate. Timed traps can be used with visual cues like a count down timer, or auditory cues which happen before they are sprung. These traps give your players a lot of room to role play since they have manufactured pressures and their characters need to work out a solution together before things get really hairy.

In most cases where you would use a time trap, the trap is either already actively running or a primary trigger starts the timed portion of the trap. Either way, these traps add a lot of fun elements to a session. Be sure to give your players good indicators to the timers as they they progress so that are always aware of the time they have to both think and act.

Spell Trigger

While many of the traps we talked about can have a spell trigger, the spell trigger itself also covers a wide array of specific spell classes. From 3.5E, the spell exploding runes was one such trigger: it went off when read, which implied if a player couldn’t read then they could not set it off. In 5th edition DnD, the spell trigger has been updated and adapted, and spells like exploding runes have been bundled together into Glyph of Warding. Rather than describe each specific trigger here, I will defer to the Player’s Handbook for more details on Glyph of Warding. It has a lot of uses and we will certainly be revisiting it later in this series!

Next Time on DnD Trap Tuesdays

Every Tuesday following this post we will be looking at either trap fundamentals like we did today or specific examples and easy to use scenarios for you to drop into your campaigns. We will also occasionally be looking at trap design for a dungeon as a whole, giving you examples of how to make progressively building trap difficulty and mechanics that teach as you go.

You may also like