I'm building an encounter around illusions, but this works for other similar situations.

The party moves along the narrow corridor. As they turn the corner, they see just another regular corridor.

But in fact,

An illusion (like Major Image) was cast on the ground to hide a giant pit trap.

I can either ask the players to roll an Investigation check or use their passive scores. I tend toward the latter so as to not alert them something is wrong. Anyway, assume that some players indeed notice it's a trap. Others do not.

How do I describe the scene to players when they have different perspectives?

Should I assume that the players who realize it's an illusion just plainly tell the other party members? Should I use secret notes? Ideally, I'm looking for a system that fills my requirements.

  • I don't want players to know a passive skill check was just performed
  • I don't want to alert players who failed to recognize the trap that something is amiss
  • I don't want to slow down the game
  • I want the players who did recognize the trap to have the option to reveal that to other party members (they might not remember that other PCs may have not seen it, or they might want to screw over the other PCs)

3 Answers 3


Passing a note, especially one you've prepared ahead of time, is a standard way of handling secret information. However, I recommend you just tell the players in the open.

Unless you've got a campaign and group that is specifically interested in backbiting and infighting, there's no reason to jump through hoops to give people the chance to not mention a specific trap. It's almost always better for the game for the perceptive PC to just warn the others.

Being open about the situation gives the players of your perceptive PCs a chance to show off the usefulness of their skills and gives players of the less-perceptive PCs the chance to roleplay their obliviousness (or not, according to their taste).

Even if your players do want intra-party rivalry, I find that it's more interesting for the players to have all the information in the open. That helps ensure that everyone is truly consenting to the conflict and it's not someone being cruel OOC.

Usually, the only time I keep information secret from the group is when it will result in a cool dramatic ideal later on. I just had a PC revealed to have been working with a gray-morality group for OOC years, which was a fun revelation for the group. Other than that, though, I find being open with information is better.

  • 8
    \$\begingroup\$ I thought I addressed this issue in my answer: I'm not robbing the players of anything. The players can still RP the scene, and the PCs still have to talk to each other. They're just doing it with everyone understanding what's going on, instead of some players not knowing what story is being told. Is there a way I can make it more clear in the answer that I think the RP is better when all the players know what's going on even if some PCs don't? \$\endgroup\$ Mar 17, 2017 at 15:30
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    \$\begingroup\$ @Slagmoth I don't agree that telling all players out in the open that there is a trap robs the PCs of an opportunity to RP. My group roleplays through such situations perfectly well. Hidden information has its place but I don't think it's necessarily the best for every trap the rogue spots. As Gregory points out, I think RP is improved when the information is out in the open as it lets players who aren't aware roleplay their lack of awareness. If they don't know that they don't know, all they can do to react to the trap is nothing. \$\endgroup\$ Mar 17, 2017 at 15:30
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    \$\begingroup\$ I like this answer and have already upvoted it. I think it would be improved with a little more explicit treatment of the difference between player knowledge and character knowledge, and how your players successfully navigate that. \$\endgroup\$
    – nitsua60
    Mar 17, 2017 at 15:37
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    \$\begingroup\$ I was more or less indicating that there are more than the single polarizing reason to only tell the person that sees a thing (trap, invisible creature etc) than just in-fighting and back-biting. First it keeps the player vs PC knowledge more organic. What I tend to do is ask the player if they are ok with me overtly stating it rather than covertly informing them, but it is ultimately the players' decision in my opinion. For invisibility the PC that sees it may not know the others do not as See Invisibility just says you see it... not that you know it was invisible after all. Fun RP stuff. \$\endgroup\$
    – Slagmoth
    Mar 17, 2017 at 16:02
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    \$\begingroup\$ +1 If there is party in-fighting going on, this keeps in "in character" and not "out of character", as the perceptive party member announces with a smirk "I /don't/ tell the rest of the party about the pit trap". Unless you have significant issues with meta-gaming in your group, the rest of the group will just follow along, and fall right into the pit trap. \$\endgroup\$
    – Shem
    Mar 17, 2017 at 16:09

Spells Typically Require Investigation Check

The illusion spells clearly state that an investigation roll has to take place, so they all see the illusion unless or unitl someone says they want to search the passage for anything amiss or search traps. Passive isn't good enough for spells like Major Illusion, and they have to specifically call out using the action ("I'd like to see if there are traps or something is a miss in this passage.") to make a check roll.

A creature that uses its action to examine the image can determine that it is an illusion with a successful intelligence (Investigation) check against your spell save DC.

Traps May Be Found Passively

Other traps may be found with passive perception. You typically shouldn't call for a perception or investigation check unless the player DO something actively to cause the roll. Some DMs do, but this isn't what the rules say to do.

Getting Information to the Player

If a player does investigate and you want to keep the results secret from the other players, you can whisper in the players ear or hand them an index card with what they find out. If you really want it to be a secret and are using cards and whispers you also have to use them to say they see nothing out the ordinary.

If it is a basic trap, and you trust your players not to meta game, saying it in the open is fine. I've done both, as long as the players know the characters don't know the information until the player who say it says something. Reading Gregs answer before this edit and really thinking about it again, I may be preparing less cards in the future.

What I do (and where I might put trap)

Personally, I try to keep everyone in initiative order through areas with traps. To make this not quite so obvious, I try to place traps after areas where I anticipate combat, and I try/hope that a monster can flee through the corridor where the traps are hidden. The thought being they will think I'm keeping them in rounds because of the monster, so see if they can catch it or not. In order for this to work, I try to keep them in rounds anytime a monster escapes anyway -- if they catch the monster, battled continues and we don't have to re-roll init.

Of course, if everything is dead, I don't keep rounds going as that would be a tip-off.

If a player asks to investigate, I hand them a card (or more likely whisper something to them, because I only have so much prep time and can't make cards for everything. I like whispering "It looks like a hallway" when it is clear or they fail the check -- the other players then thing the player knows about a trap, when they don't). But even if you just tell them in the open, the other player's characters still don't know, so rest would still apply.

I also not let anyone say more than 6 seconds of dialog per round (not very strictly -- but if someone tries to explain a complex thing and it is taking too much time)... All of this it can on occasion create a situation where the player who knows starts to say, "Don't it's a ..." and then the player falls for the trap anyway.

I also place traps at places where naturally whoever built the dungeon/temple/castle/etc. might place them to protect something. These I don't expect to actually cause problems for the player, but instead the players would begin wondering why there is no security around this valuable artifact... Sometimes, however, even these catch players off gaurd, and be a source of fun/drama.

On using Traps Sparingly

Remember to use traps sparingly, so that the party doesn't begin searching every room they ever walk into for traps.

DM: You're in a tavern, the bar keep is a...

Player: I search for traps and hidden passages.

DM: The bar keeper says, "Why are trying to look under every table? Ya see a rat or something?"

Player: I insight check the bar keep.

DM: The bar keeper says, "Why are you looking at me so intensely? Are you alright? I think you've had enough, and I haven't even served you yet."

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    \$\begingroup\$ Do you have players take every action in a dungeon as part of a combat round? That sounds somewhat tedious. \$\endgroup\$ Mar 17, 2017 at 15:17

What's wrong with simply telling the players whose characters passed the passive check what they see? They can choose to tell or not tell the other party members. I would assume that in almost every case, the PC who spots the trap is going to inform everyone else in the party (unless they're evil). If your players are good sports they'll play along even when their characters don't know about the trap.

As for knowing or not knowing about the passive skill check, won't they only know if you tell them? Otherwise, won't they know once you tell them only certain PCs spot the trap? I don't think there's a way around this.

It's up to you and your group to make sure that the PCs who did not see through the illusion don't act on their out-of-character knowledge.


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