How do I design traps or dungeon rooms for a party with remote manipulation abilities?

Question

The party that I'm DMing for has access to a lot of remote manipulation abilities, such as mage hand, telekinesis, and familiars. Because they are smart characters and smart players, they have used these abilities to defeat a wide variety of classic traps and trap triggers.

For example, mage hand is easily able to remotely disable tripwires. A few extra rounds of telekinesis is enough to disable most pressure plates. A disposable familiar can easily scout out a new area, and summoned creatures can be used to tank otherwise unavoidable damage. All of these abilities can be used from a safe distance, or at least far enough away that it's hard to predict where the "real" target will be standing.

I don't plan to completely remove such traps--they still require good gameplay and table engagement, and can still be rewarding to defeat. I'm also aware that some of these solutions consume resources.

However, I find that the process is becoming a bit predictable and rote: players encounter something, back up to a safe distance, and then fiddle with it for a while until they're sure that it's safe.

I would like to mix it up a bit and design traps and encounters that are immune to this kind of remote manipulation. I'd like to try to come up with an encounter or trap that can't be defeated by fiddling with it from a distance. Unfortunately, I'm not sure how to do this.

How have you designed traps that force your players to deal with it up close (or at least within vulnerable range)? How did they work in practice?

Answer 1

It sounds like you're over-using the 'hits the guy who triggers the trap, no reset' variety of trap. There are a lot of other, more exciting traps you and your players may find interesting:

'does something insidious but not immediately apparent, no reset'

• When the players press this pressure plate, the ceiling of the entrance corridor to the dungeon seals shut, trapping the players inside. It will not reopen for 3 weeks, and if more than 10% of the stone is excavated it will not reopen at all. Hope your party brought supplies!
• 10 minutes after this ward is breached, this section of the dungeon begins filling with (choose one: water, sand), which pours in via a mystic portal to the Plane of (Water, Fire). The substance continues to pour in until the body of material reaches the vaulted ceiling of this room, blocking access to the portal and causing it to shut off. If the material is somehow diverted, the portal closes 10 minutes after activating. The portal can transport up to 3 10' cubes worth of material per round.
• Once this tripwire is triggered, an alarm is triggered far off in area 3, alerting the bugbears to the presence of intruders and allowing them to rouse their companions and prepare an ambush.

'does something obvious, but resets and continues to pose a potential threat'

• This pressure plate triggers an arrow trap that fires down the corridor. The arrow trap is set to automatically reset each round, and holds a reservoir of 500 arrows (worth 12.5 gp if the party empties the container by triggering it and salvages the arrows). If the hobgoblins fight in this hallway, they attempt to form lines so the PCs closing with them will be forced to trigger the arrow trap.
• This door is infested with Ear Seekers. Anyone touching the door transfers one of the foul creatures to their clothing on a failed reflex save (90% chance if the infestation is unnoticed by the party), and anyone attempting to listen at it is automatically affected.
• When the ward is breached, the warded area appears to fill with whirling darkness and a piercing shriek can be heard. Under the cover of darkness, a set of scything blade traps attack everything within 10' of the center of the room. The darkness and shrieking is illusory, but the scything blades are real. The blades retract as soon as the room is unoccupied, at which point the darkness appears to drain back as if through a portal. The wards trigger again if any creature again enters the room.

'does something insidious, continues to pose a hazard'

• This "pressure plate" is actually a rather intelligent mimic sitting in a floor cache that contains the level used to open the secret door to area 4. If the party presses the plate remotely or appears too difficult a fight, the mimic pulls the lever and opens the door. If the party appears weak, a single character attempts to pass through on their own, or the party has brought pack animals, the mimic attacks, first using its control of the secret door to isolate its victim or victims from help.
• This bookshelf contains a translated copy of the ancient play 'The King in Yellow'. Any character reading the first act of the play finds it quite mundane but vaguely unsettling, but anyone reading even a word of the second act feels compelled to ensure the play is performed. This functions as a Suggestion spell cast with a 9th level slot except that it is a 9th level effect, functions even on creatures incapable of being charmed (though they possess advantage on the saving throw), lasts until the creature witnesses a full performance of the play, and can be removed only by Wish, Greater Restoration, Heal, or Dispel Evil and Good cast with the additional verbal component of the long-lost name of the eponymous king, thrice spoken. Warlocks with the Thought Shield feature are immune to the book's effects

Lastly, you can always use traps that hit someone other than the person triggering them, for example casting fireball or filling an area with toxic gas or otherwise generating an area effect, but that isn't terribly much different from what it sounds like you are doing now, and will just lead to players standing a little farther.

Answer 2

tl;dr

Don't worry about it. Added layers of complexity will help solve the problem easier than you might think.

The Answer

I wouldn't think it's a problem for things to be manipulated remotely, as you think it will be. Why not? Because it's unlikely that they players will be able to figure things out to the extent you think they will as quickly as you think they will.

Are you familiar with the Apparatus of the Crab? Take that as inspiration for how the traps work.

Let's say that a familiar and an animal companion are turning knobs, pulling levers, and manipulating switches. Even one working by itself, it can take some time to be able to figure out the appropriate ones to work and in which order.

1. Complicated Controls

   Furthermore, there can be ways of changing the controls, something akin to how in video games you can change which buttons do what. Have one knob or switch reverse the order it did previously. For instance pushing something up that caused a platform to raise, might cause it to lower because a knob's been turned.

2. Interactive Controls

   Another way to change things up is to have the control scheme change every so many moves, so the players have exactly X number of moves before they start anew figuring out the new pattern.

3. Interconnected Controls

   A final idea is to have multiple control rooms, and one affecting the controls of the other, so the players and familiars or companions have to work together.

The OP said that they don't want the players to be able to work from a distance, out of harm's way. The point of the answer is that the PCs would be endangered in such a scenario. Walls moving suddenly might cause the PCs to get squished by them, platforms raising and lowering unexpectedly might cause those on it to fall off and injure themselves. A gate opening might release a monster that attacks them.

Even with the druid's/ ranger's companions or wizard's familiars manipulating things, doesn't mean that PCs controlling them will be able to communicate with them. Maybe the control panel rooms is lead lined... or designed in such a way that it somehow blocks communication between the master and the animal / familiar in question, so buttons are being pushed and levers adjusted randomly. Maybe too, the familiar / animal companion can't understand the layout because it's simply too complex.

Answer 3

I see several ways to challenge such parties.

Simple Solutions

• Antimagic fields - These flat out prevent use of magic to disarm
• No Line of Sight - most spells in D&D 5E require Line of Sight to function.
• Requires use of remote manipulations - if you have to have two mage hands to disarm, you now have two casters having to coordinate
• Requires a strong pull - In older editions, it was specified as STR 1; 5E is less explicit, but the implications of 10 lbs carry limit is under STR 1. So say it needs 30 lbs of pull, and it's not going to work.
• Requires fine manipulations
• multiple simultaneous switches. Mage hand only allows one of them.

More involved

• Negative Visual Illusion - the mage hand goes through an illusion - you cannot see through it unless you REALIZE it's an illusion. An illusion of what is behind the illusion can trip up the unwary, and may be mistaken for an antimagic field. Combine it with an AM field for even more fun. • Area Effect on failure. Remember the LOS requirement? Well, if the trap affects the whole area in LOS... (I used this with a kerosene drop in a T&T game...)
• Failure summons help - a complex trap, but one that multiple repetitions can defeat - but failure summons (quietly) help... who then show up and make it "advance or be taken here"...
• Fakery
  • Fake Levers - Sometimes, the disabling levers do nothing.
  • Fake alarm - Sometimes, they make a loud noise, but only really audible in room.
  • Fake Threat - an Illusion of a poisonous cloud can be great fun.
  • Fake on success, Real on failure - it looks just the same succeed or fail, but on success, it's an illusion (which the creators know about, and so are immune to); on fail, it's a real version. Either way, hilarity may ensue... or accusations of being «unkind words withheld by author»...
• No defeat by physical means -
  • Talk your way past the talking door.
  • successfully dance across the floor tiles, which require 50 lbs of pressure... in the correct
  • Feed the rapid regenerating troll wearing the Ring of Fire Resistance to get past him
• Failure does something unusual
  • Failure to disarm triggers a portal behind the trapped door... and behind the entrance door, and both kick you to 10' above the entrance... take a d6 damage, and cast some antimagic to get by.
  • Failing the trap still opens the way - it looks like you succeeded, but when you go through the protected portal, THEN it does something nasty.
  • Failing the trap alerts the defenders, but still opens the door.
  • Failing the trap summons some holy extraplanar to give a lecture... Sure, they can try to kill it...