Aside from wanting to try some pbp roleplay for a difference, I am also a slacker tabletop GM during my free time. I am currently planning an adventure in a self-created setting, where at some point players will have to venture through a dungeon created by gnomes to ward a huge shard of crystal in ressonance with four others hidden in different locations.

The trick is that I expect the party to arrive at this dungeon by level 8-9 to fit the main storyline, but I'm having some trouble coming up with a challenging puzzle dungeon for them. My best ideas so far are either bland (a series of rooms full of misc clichéed deadly challenges) or are so extraordinary that fail to fit the adequate CR. Could you lend me some ideas?

Pointers:
- The dungeon was supposedly built by gnomes and magic alone in a time when the world had a lot more high-level arcane spellcasters and, thus, it is supposed to reflect this advanced magic environment.
- I'd like this dungeon to be clever. Something that would need more than either simple strength or skill to be cracked. Also, the intelligence bypass would grant them easy access to the crystal shard without the risk of being zapped by their own creation
- This is entirely optional, but it'd add a dash of realism to include a tiny-weenie-bit of humor because... well... gnomes built it and the way I roleplay gnomes they enjoy their share of shenanigans. In this case, probably with a dash of dark humor. By my book, gnomes don't play it dull.

I'm really at lost here. Any ideas are good!

Well ya could go with a "house of horror" version, not talking actual horror though, talking the themepark type, have their characters get scared senseless by fake monsters, only to have them realise it's not real and that they are whacking at a piece of scrap metal that's really of no danger to them, but have them realise it by them not actually taking any damage from it's attacks, that the attacks it does is in reality an illusion, see how long before one of them catches on to the fact that they are not taking any damage.
That is for the humor part.
As for the puzzle part? Hmm no idea all I can think of that fits a gnome design is well, kind of cliche.

Throw so many Illusions at them that they doubt their own existence. Check out what spells can be affected by Permanency, then think of what you can DO with those spells!

I guess that is another approach xD.

Small creatures build Small dungeons.

I'd really take this into greater consideration if the campaign had less elements of horror. By the time the PCs arrive here they have probably seen their share of horrible scenes and the typical lovecraftian themed sidequests. I'm still considering this because it is funny, creating the illusion of enemies while there are none and the illusion of safety when there's real danger around fits the illusion theme.

If i do this by the book, Permanency affects a measly three illusion spells: invisibility, ghost sound and magic mouth. There is vast potential for each and every one of them, but they only go as far when it comes to put the players into nihilistic state of mind. If I am to work with permanent illusions to create this dungeon, I'll have to bend the rules a little. Hopefully players will care more about the final result rather than argue with the rules.

Totally agree, and DMs often forget that small-sized creatures usually don't build for medium-sized humanoid confort. Also, medium-sized creatures fighting in a tiny corridor hampers mobility and difficults combat maneuvers, so it is a great way to make low ECL encounters a lot more challenging.

Ok, so I've been considering your opinions and browsing other threads for possible ideas and came up with these:

- A friend of mine suggested a dungeon carved like a wind instrument (like a giant trumpet), where the small-sized corridors were the tubing and large round-shaped rooms with a pressure-plate mechanism worked like pistons to produce a sound and players would have to play a certain tune to open the door. The trick would be to get the certain number of players in the correct order of rooms to play a certain tune to open a door. However, put the wrong number of players inside the piston rooms and the discordant sound could create either a disruptive sound (too many players) or a key so soft it could induce long-lasting mind affecting effects, such as illusions, which could accumulate and difficult the resolution of the puzzle and eventually turn players on each other (fewer players). This sounds okay but it sounds like a dungeon that could be featured in Legend of Zelda.

- In FF IX there's this dungeon named Ipsen's Castle where things were reality was reversed and "the world was upside-down". Ipsen's castle featured a series of upside-down rooms and Escher-based corridors to create a confusing environment. There, the lower your attack power is, the more powerful you are and the lower the CR, higher the challenge. This could work just fine and I can totally picture players panicking over a pit fiend encounter at such low level, while the true threat is the pathetic-looking lemure. The escher-like rooms and corridors could be the work of illusion abuse - so many illusions cramped into the same space it creates the appearance of players having entered an impossible reality. However I know this will be a hard nut to crack in terms of strategic movement: it is hard to follow an Escher painting, harder to imagine a party of PCs getting there and eventually getting lost from each other, now try to picture a random encounter there.

-...something with mirrors... dunno what XD

- Any other idea.

What do you think? Have any other ideas?

Perhaps the gnomes used a Permanencied Phase Door to bypass the traps and illusions, leaving everyone else to do things the hard way.

Bah, I was thinking of Permanent Image earlier. It can't duplicate tactile sensations, but it "includes visual, auditory, olfactory, and thermal elements". This spell is made of win.

Exactly, it could be pretty hilarious, I would love it if a GM did something like that.

I've always wondered: aside from the occasional monster with thermal vision, what's the point of mimicking thermal elements if it can't duplicate tactile sensations?

It fools blindsense and blindsight. I'm not sure it would fool tremorsense, and it certainly can't fool lifesense or mindsense.


Besides, when you run into a creature that DOES see in thermal vision, you'll need all the help you can get.