Monster reccomendations?

[Yalius]

The corridors will be one foot high? OK, now that's insane. I wouldn't go into that for love or money. You can't even crawl in that, you have to inch along on your belly, and even a normal-sized human would be scraping the top and bottom as he did. Even a halfling would be crawling! And air circulation would be almost nonexistent. And nowhere does it get any higher than 3'? That's just brutal.
Putting myself into my character's shoes, I couldn't do it. I just couldn't make myself go into something like that. I never thought I was claustrophobic, but sheesh, that dungeon would leave me a babbling wreck.

 

[KrazyHades]

HeavenShallBurn, the party is NOT small, because I want them to have to belly-crawl through this level.

I like some of the ideas here, and incorpreal undead DO sound nice and mean *grins*

 

[Joshua Randall]

Jermlaine. Boggles. Quicklings, redcaps, and other evil fey.

I know jermlaine are in one of the WotC monster books (FF?); not sure about the others.

There's a template in Dungeoncraft that lets you miniaturize monsters... you could shrink down some larger creatures a couple of times (assuming the template lets you apply it multiple times).

 

[Ravilah]

I'd have a few places on that level where the PCs could stand normally and get over their claustrophobia. They will feel safer here, and will be inclined to loiter in such places.

Of course, the place will be a great big, nasty trap! Muwahahahahahaha! If they fall asleep there, they won't wake up until the gremlins (or spiders! or halfling vampires!) come and take them away. They wake up hours (days?) later trapped in a space so tight, it's like being in a coffin. Or maybe it is a coffin!

It reminds me of a small dungeon I made for a one-off once. It was the lair of Mome: He Who Comes For You.

 

[KrazyHades]

That sounds deliciously cruel...I'm going to do it! Thanks for the idea, Ravilah!

 

[TarionzCousin]

HeavenShallBurn, the party is NOT small, because I want them to have to belly-crawl through this level.

I agree with Yalius: no character I would run would be willing to belly-crawl through a dungeon level ... unless the Head of Vecna were guaranteed to be waiting at the end of it.

 

[mfrench]

As a 12th level PC, I don't think there's any way I would go into a 1' high tunnel unless I absolutely had to. Just off the top of my head, if we couldn't figure out a way to teleport past this level altogether, I would use either:

a) Wind Walk, can take caster and 4 others in gaseous form, move rapidly
b) Polymorph into something that can burrow, try to avoid this level
c) Go Ethereal and search for the next level
d) Use Passwall to try and dig if we must

At that level, they have a lot of magical might that they can bring to bear on a situation like this. If pressed for time, they might not have any of this prepared, so they could be forced in. It just seems like such an obvious deathtrap that a PC would have to be pretty desperate or pressed for time to put themselves through this (regaredless of what cool stuff you filled it with).

As a PC, I'd also want to know what movement rate I'd have, what weapons could be wielded, whether direction/facing was enforced, etc.

Edit:
Not trying to rain on your parade, just listing the concerns from a player point of view. Plus, don't want you to plan out a huge level just to see the PCs make it irrelevant with something you haven't thought of!

Also, I would be inclined to do some scouting first with a summoned creature, hopefully an Earth elemental.

 

[KrazyHades]

Yah, I can definitely see where you're coming from, mfrench. They're supposed to not want to go in there, but they have to if they want to get the things they need for a puzzle (of sorts...find and replace the 3 runes that have been chipped out of the door that leads to the next level, allowing it to open). The creatures in here will be at the average party level or one level below (because I DM for a group of 8 people...) because the CR is increased when the monsters have such a clear advantage with the terrain. There's also some nice treasure in this level, a further temptation.

It looks like a deathtrap, but with a little planning they can bypass it without losing a character. And the players in my group can be very gung-ho about charging in to situations (especially ones far above their CR...ahh, good stories)...I doubt that they will attempt to totally avoid the level, though they may come up with an ingenious plan to get through unharmed.

The players really love the kind of horror feel that I add to my dungeons to make them seem far more frightening and deadly than they are, so I know that they will LOVE going through this floor (though the PCs might not)

 

[Jhaelen]

The corridors in this floor have 1 foot ceilings, and the rooms have 3 foot ceilings. This inhibits movement and combat. The area is also pitch black, and filled with small, stealthy/invisible creatures that strike from nowhere and then disappear.

I've used a hive of cranium rats to good effect in a similar environment.

 

[Gez]

Also, I would be inclined to do some scouting first with a summoned creature, hopefully an Earth elemental.

Or a thoqqa. If you speak ignan or terran, you can tell it to burrow just next to or below the small corridor, in effect widening it by one foot. That way, you both scout and make the tunnel a tiny bit more comfortable.

At level 11-12, stone shape and disintegrate can likewise be used. The downside is that progress is slowed by the limited availability of spells per day, so if the players don't go ethereal a ticking clock may force them to crawl anyway.