You're at the bottom of the catacombs with the bookcase?

It's an unfinished area currently, so unfortunately the only way to proceed is to climb back up and leave the way you came.
Messing with the bookcase does trigger events though.

Just found this one out while trying to put together my post on cheating at sumo wrestling:

The site is using HTML tags for formatting, but the two list buttons generate markdown rather than HTML tags.

For example, pressing the bullet point list button produces:

* Item 1
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Rather than:

[list]
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Today I finally discovered a legitimate way to cheat during the sumo match, and along with it a way to kill off the audience of the sumo match without any consequences.
And all within the latest release of vanilla IVAN.

The big problem with trying to cheat at sumo wrestling before was that the old devs had thought of basically all the ways you could have cheated or given yourself an unfair advantage during the sumo wrestling match (haste notwithstanding) and had put in safeguards to prevent you from doing so:

• If you sneak in, any items dropped in the arena are automatically cleared out once you leave. This means you can't leave a weapon or wand at the entrance to give you an unfair advantage over Huang Ming Pong.
  
• The structures inside the sumo arena belong to New Attnam, so setting traps or damaging the walls in any way causes the town to become angry, which in turn means that you will never be able to challenge Huang Ming Pong. This stops you from being able to set traps or consistently/safely leave acid on the floor for Huang to stand in during the fight - breaking a bottle of acid inside the arena is likely to get some on the walls, which means the town will get angry when that wall inevitably melts.
  
• Not that this is normally ever possible, but attacking the audience, stealing a lantern or damaging the arena will cause you to be instantly disqualified.
  

However, after a little bit of experimentation I found that once again, gas grenades have proven to be the number one choice for exploiting the game!

The necessary items to cheat at sumo wrestling are as follows:

• At least one mustard gas grenade (the more, the better)
  
• A way to sneak into the sumo arena (food to lure Huang outside / invisibility)
  

And to kill off the audience:

• Wand/scrolls of teleportation
  
• Ring of teleportation control (optional, but useful to ensure you don't get stuck outside the arena)
  

Once you have collected the appropriate items, follow these steps:

1. Become bloated or overfed.
2. Sneak into the sumo arena.
3. Throw mustard gas at the northern wall - if you want to kill the audience, use your teleportation items to exit the glass arena and gas the southern wall.
4. Exit the arena.
5. Challenge Huang Ming Pong to battle.
6. Watch everyone choke on mustard gas - if you're trying to beat Huang Ming Pong this isn't going to clinch you victory because he'll descend upon you like a raging gorilla and punch your spine out anyway, but now he'll be taking damage every few turns from the mustard gas too. You might also want to try skunk smell grenades to maximize the damage over time.

If you've gassed the audience, victory will trigger the moment one of them dies - the code doesn't care about WHO dies in the sumo arena, just that someone does. Usually this is Kaethos or the child tourist.
Once you've exited the arena, it's likely that all the other audience members will die from mustard gas exposure within a few turns.

This works because much like liquids, gas clouds persist even after you have left a dungeon level.
In addition to that, you are not subject to normal hostility rules during the sumo battle, to facilitate you being able to fight Huang Ming Pong without making the town mad.

SPOILER ALERT. Click here to see text.

SPOILER ALERT. Click here to see text.

Heheh, I wrote that entry. I'll give a very big hint, and a spoiler with the actual answer(s).

If you want a hint, the others have already pointed you in the right direction - there's certain types of creatures that can eat bones. Consuming Ommel bones/teeth will give a permanent buff to your stats, just like all other ommel materials.
But how could you eat bones if only certain creatures eat bones? You are only human after all.

SPOILER ALERT. Click here to see text.

As a side note, I think it is actually a good idea to put down the specifics of how to do it on the wiki somewhere, but I'd prefer to have it on a "Secrets (SPOILERS)" page instead of any other regular pages.

Sounds like it's actually ommel fluids.

I agree, there should be an item you can apply on yourself to soothe burns and you should be able to get them healed for a price at a healer - just like how Antidote Liquid and priests work for other nasty problems like leprosy and lycanthropy.

However, having to remove and replace your limbs is pretty brutal. Pretty fitting of IVAN.

Also it's likely a waste but SoCMimg the limb should fix it up good as new. Using a flesh material would even keep its natural stats.

So far as I know you're going to have to remove the affected legs and grow them back or get them replaced by a god.
Not sure how you're going to accomplish that though, pretty sure world map guy is SoL. Beebelbrod can probably get away with stepping in bear traps or broken glass with no boot on that leg.

If we're going to include the Tweraif liberation stuff, I personally think it'd make for a better big sidequest than an actual ending to pursue.
That would mean lining up a decent reward for doing so.

We can explain away Petrus (and by extension Attnam) not getting mad as a result of this because it takes forever for messages to get to Attnam anyway and he already thinks Decos is a lazy bastard who may or may not be embezzling some of the banana profits.
By the time he thinks to investigate why he isn't getting progress reports the player may already have beaten the game, and Silva's protection would be in place.