Portable hole trap

[Darth Credence]

I've designed a trap, and I'm looking for feedback to see if I should use it or not.

Somewhere in the wizard's tower, the PCs come across a 10' deep pit. It looks to have been carved out of the bedrock, with rough stone along the sides. The top is covered by a metal grate with a trap door locked by a padlock. Inside, the PCs can see a number of chests, and some various goodies are in plain sight.

What they are actually looking at is the interior of a portable hole, which the wizard has used stone shape to build false walls that make it look like the area has been carved out of the rock. The chests contain nothing but rocks. The idea of the trap is that the players will think it is something worth something, and they will proceed to bypass the lock and climb down in. As soon as one of the players with a bag of holding crosses the hole, their bag is destroyed, and everyone within 10 feet ends up scattered on the astral plane. Sure, it's expensive, as the wizard is sacrificing a portable hole, but since most characters of a high enough level to be a problem will have their own extradimensional space of some sort, it can remove dangerous individuals from the tower without necessarily killing them.

I am thinking about using this in one of the side missions that we regularly do to establish things in the world. The players will be playing some evil PCs, and will be assaulting the tower of the mentor of one of the regular characters (I've already discussed it with that player, and he likes the idea of the mission, even if it means dead mentor). If they get sent through and it really screws them up, it doesn't really mess things up.

Any thoughts?

[Kurt Kurageous]

I've designed a trap, and I'm looking for feedback to see if I should use it or not. Any thoughts?

First though that came to mind before reading anything was, "Traps suck."

You may enjoy them, but players hate them. Can you foreshadow the trap so they have a chance to avoid it? Example, for an arrow trap. Party sees broken arrows without flights, then sees a dead skeleton shot with arrows without flights in front of a broken open trap with a crossbow and a rotting chest. Next they see a room with a chest. If they had been paying attention, they will pat themselves on the back as they defeat this trap.

If you don't give them that chance, your game will slow to a crawl as the party will check absolutely everything for traps because you gave them no chance to find it otherwise.

And I see no way you can foreshadow a unique never before seen trap like you have described. Find a way, and it might be fun.

[Darth Credence]

First though that came to mind before reading anything was, "Traps suck."

You may enjoy them, but players hate them. Can you foreshadow the trap so they have a chance to avoid it? Example, for an arrow trap. Party sees broken arrows without flights, then sees a dead skeleton shot with arrows without flights in front of a broken open trap with a crossbow and a rotting chest. Next they see a room with a chest. If they had been paying attention, they will pat themselves on the back as they defeat this trap.

If you don't give them that chance, your game will slow to a crawl as the party will check absolutely everything for traps because you gave them no chance to find it otherwise.

And I see no way you can foreshadow a unique never before seen trap like you have described. Find a way, and it might be fun.

I agree that as a general rule, traps suck. But, I think that used sparingly, they are good, and my experience with my player group is that they have never gone down the route of check everything. In our 18 months of playing this campaign, there have been two places where traps were a factor. Both of them involved kobolds - once at low levels, and once just recently. In both cases, we all had a great time, with the recent one being a definite highlight of the campaign (the kobolds were a bigger problem than the young dragon at the end).

All that said, I agree that foreshadowing would be ideal here. I can easily foreshadow in a meta sense, because the group are currently playing their regular characters and are with the mentor in the tower. They are discussing the state of the Macguffin coins, and I could have the mentor assure them that they are well protected, and anyone who attempts to get them are in for a huge surprise that will banish them from this world. The evil characters will be able to pinpoint the location of the coins, which are buried in the ground beneath the hole. So if someone is casting a spell to find them, it will point to the bottom of the hole, but they are actually buried at that depth, and to get to them they have to remove the hole. My biggest worry with that is that they tend to be pretty scrupulous about not metagaming, and may actually decide to not look for the trap simply because they know as players but not characters.

I could put in a different room in the same general area that is basically empty except for the shredded remains of a portable hole and a bag of holding, and let them try to figure out what it meant.

[Mellack]

I don't see how it is possible to stone shape the walls of the portable hole or do anything to them at all. The hole is not actually the stone, and its dimensions are listed by the object. The cylindrical space within the hole exists on a different plane, it is not actually the material there at all.

[Darth Credence]

I don't see how it is possible to stone shape the walls of the portable hole or do anything to them at all. The hole is not actually the stone, and its dimensions are listed by the object. The cylindrical space within the hole exists on a different plane, it is not actually the material there at all.

It wouldn't be stone shaping the walls. It would be stone shaping other stone that he has around to put up against the walls, so that it looks like it is just carved out of the bedrock. That is the kind of stuff I need to think about before implementing this, if I ever do, so thank you for pointing it out.

[kingcheesepants]

I'm not clear on how the players being scattered to random locations in the astral plane wouldn't mess things up. That's potentially campaign ending right there. I like puzzles in general whether in the form of traps or otherwise. But you need to be very careful when putting in instant death traps. And this one is actually worse than your standard instant death trap because there's no save, no body to revivify and it will possibly hit more than one character. The only reason to put this in is if you have an astral plane adventure that you'd like the group to do and then this can be the way that they get started on that adventure. Otherwise you're just risking getting rid of a character or two because they failed to investigate their surroundings appropriately.

[elyktsorb]

This is absolutely a trap 'I' would have in my wizard tower if I were an actual wizard, this is not a trap I would throw in front of players if they have no means to recover from it.

[Potato_Priest]

This is an ingenious trap, and a very sensible thing for a wizard to have. I commend you, sir!

However, as others have pointed out, this is a terrible trap to use in 90% of campaigns as having your player scattered on the Astral plane really sucks.

[Darth Credence]

Maybe I'm missing something about the astral plane. As I read the DMG, the plane has pools around that lead to other planes, including the prime material plane. And that it is a matter of luck to find one to the correct place, that will take 1d4*10 hours of travel to get there. So at most, the players will have to spend a few days looking for a portal home, and then they'll find it and get back to the correct world. Once back in their world, they should have the ability to reunite. They also have, and continually refresh, Rary's telepathic bond, so for the first bit on the new plane, they can communicate and formulate plans, then two of them have access to sending and can talk to everyone other once they make it back out. I see it as at most delaying them for a few weeks while other things continue to happen, but unless they get themselves killed by githyanki or something, this is not going to lead to character deaths or the end of the group.

Is that not correct? If it isn't, and I am running the risk of everyone dying because they can't get home, I'd abandon the idea.

[chiefwaha]

I'll let everyone else debate the idea of whether this is a good idea or not, but here are my thoughts on the thread already...

First, make the walls an illusion. Heck, make the treasures an illusion too. Give them that as a potential hint.

Second, put a bag of holding somewhere outside of the portable hole... The wizard would want to make sure his expensive trap would go off, since there would be no actual way to determine if the trigger mechanism would enter in otherwise. If you really want to hit them over the head with it, put it right outside the trap somehow.

[kingcheesepants]

Maybe I'm missing something about the astral plane. As I read the DMG, the plane has pools around that lead to other planes, including the prime material plane. And that it is a matter of luck to find one to the correct place, that will take 1d4*10 hours of travel to get there. So at most, the players will have to spend a few days looking for a portal home, and then they'll find it and get back to the correct world. Once back in their world, they should have the ability to reunite. They also have, and continually refresh, Rary's telepathic bond, so for the first bit on the new plane, they can communicate and formulate plans, then two of them have access to sending and can talk to everyone other once they make it back out. I see it as at most delaying them for a few weeks while other things continue to happen, but unless they get themselves killed by githyanki or something, this is not going to lead to character deaths or the end of the group.

Is that not correct? If it isn't, and I am running the risk of everyone dying because they can't get home, I'd abandon the idea.

Well you're the DM so it's up to you how dangerous the astral plane is and how easy it is to find a portal back some viable place that the party can get to. If you want to just handwave it and roll some dice and say it takes 2 days to find a portal back and then that portal opens up near a city that the party has access too then you can certainly do that and the trap isn't such a big deal aside from the inconvenience of waiting around.

But generally speaking the astral plane is dangerous, especially for people running around solo. You mentioned the Gith but they're honestly the least of ones worries when traveling the astral plane, there are a fair number of monsters that could be a challenge to a group and will absolutely destroy a single adventurer. And do bear in mind that everyone caught in the trap (which will likely not be the whole group) will be sent to a different random place. So the party will be split into a few people who didn't get caught in the trap and then the people who got sent alone into some random area in the astral plane. Splitting the party is a bad idea at the best of times, but splitting them into groups that aren't even in the same plane is just asking for trouble. Also Telepathic Bond doesn't work across planes so the group will have to use extremely inefficient means of communication such as sending relays to talk to each other. And then there's only a 10% chance of the portal you find even going to the material plane and who knows where in the material plane it will go? The moon, the middle of the ocean, the underdark, a forest in some far off country, the top of a mountain. It could be anywhere and then reuniting with said party member could be another adventure unto itself.

So as I said before, unless you have some specific astral plane adventures you wanted to do I'd steer clear of sending party members careening through the planes.

[Misery Esquire]

Second, put a bag of holding somewhere outside of the portable hole... The wizard would want to make sure his expensive trap would go off, since there would be no actual way to determine if the trigger mechanism would enter in otherwise. If you really want to hit them over the head with it, put it right outside the trap somehow.

"Oh no, the marauding evil adventurers have gotten into my Bag of Holding production area, and might make off with 2-3 each! Whatever will I *hack cough*, ahem, whatever will I do?" D: ... ;)


It sounds like Team Evil may be a one shot or nearly so? In which case "they caused trouble and then got nuked to Astral" is a fitting fridging that they can come back from more evil later on.

[Greywander]

Second, put a bag of holding somewhere outside of the portable hole... The wizard would want to make sure his expensive trap would go off, since there would be no actual way to determine if the trigger mechanism would enter in otherwise. If you really want to hit them over the head with it, put it right outside the trap somehow.
It sounds like part of the purpose of the trap was to only eliminate intruders who were powerful enough to bring their own extradimensional storage with them. You would specifically not want the trap to go off for every random hobo who wanders inside, as that would be a waste, and doubly so if you're providing both the portable hole and a bag of holding.

But yeah, to echo what others have said, this sounds like a great trap to put in your own wizard tower, but it doesn't seem fun to encounter as a player. If you do implement this, then make sure to have something suitable planned for an Astral Plan side trip, and be aware that you'll be dealing with a split party. In such a case, I might try to do a short one-on-one with each player to work out how they get back to the Material Plane, and then start the next session with everyone meeting back up somewhere.

[Porcupinata]

It does raise the question of what actually happens when extradimensional spaces collide in this manner. The book tells us what the end result is, but not how you get to that result and what it is like from an in-character perspective.

Is it a sudden thing that just happens instantly without any warning whatsoever taking people by surprise?

Is there resistance that must be overcome and you have to force a bag of holding into a portable hole against this resistance for it to happen?

Is there any kind of indicator like a visual distortion or magical sparks or anything as the two extradimensional spaces approach each other?

Since the answer to these questions isn't covered in the rules, it's presumably one of those "ask your DM" issues. Personally, I go for the second option. You can't accidentally put a bag of holding in a portable hole (or whatever combination) and have everything unexpectedly explode. They will naturally repel each other and you have to actively force one into the other for the effect to happen (like forcing the similar poles of two magnets together) pushing them together until they reach "breaking point".