Thursday, March 26, 2009

Corridors of the Cube

It seems like a safe bet the Gelatinous Cube will not be winning the current Eleven Foot Poll, so I'm going to go ahead and talk about it in the context of my favourite encounter in Keep on the Shadowfell, the Corridors of the Cube.

Ten foot square corridors are a staple of D&D. I love them dearly, but they don't make the slightest bit of sense. After all, excavation is hard, expensive work. It is not cost effective to make tunnels any wider or higher than they absolutely have to be.

Here in what is ostensibly a military keep you might have expected cramped passages, maybe four foot across, only just wide enough for two people to move quickly in opposite directions - but no, the builders have decided what is good enough for Gygax is good enough for them. You see it, too, in dwarven architecture, where the stubby little diggers have allowed themselves enough headroom to give each other piggy-back rides. Hell, the corridor in my house is only three feet wide, and it seems to get the job done.

One of the things I love about D&D is that these kind of mechanical cliches are not just prevalent, but so prevalent that entire ecologies have grown around them. In the Corridors of the Cube we encounter the Gelatinous Cube, a transparent ooze in the precise shape of the corridor. It is a ten foot invisible cube, with its edges exactly scraping the corridor walls.

Let's point out this isn't just a monster specifically evolved to live within a standard RPG dungeon. It's a creature specfically evolved to hunt adventurers in an RPG dungeon. One of the Cube's biggest advantages is its transparency. You can see right through it, which means that, like a particularly fine spiderweb, you can not even notice it's there until you've already walked into it.

That only works on humanoids. Creatures with heightened hearing - like, say, anything naturally living underground - won't be fooled by transparency, and will hear it coming a mile away. Anything that can see in the infra-red will notice its distinctive heat signature. It's only humanoids, with their reliance on traditional light sources and edge-recognition, who'll fall prey to its camouflage.

In Corridors of the Cube, we find the Cube in its natural habitat. Players enter from the north and then have the choice of heading east or west. The Cube waits in its alcove to the east, and won't be detected unless players specifically walk into that space. Once players have picked an end of the corridor to walk to, the Cube emerges and gets between them and the exit.

If they've gone east, the Cube will take a leisurely ooze down the corridor and engulf the players at its leisure. Once engulfed, players take 10 ongoing acid damage and become dazed, and have to make an escape check (Acrobatics vs Reflex or Athletics vs Fortitude) to get out. It can engulf multiple players on a single turn, and characters who escape end up back next to the Cube with their turn used up, so actually getting away from the thing is next to impossible.

If players go west, they're in for even more problems. The room to the southwest holds two Corruption Corpses, a disgusting kind of zombie that throws pieces of its own flesh from range and deals aura damage to anyone who gets close. The Cube will literally drive the players into the corpses, until they're taking the zombies' aura damage even while engulfed.

When players eventually triumph over Cube and Corpses, they get the chance to ransack the room to the east of the zombies. Here they find a collection of children's toys belonging to Ceinwein and Drystan Keegan. Reading between the lines, it's not hard to draw the conclusion that the two zombies outside are intended to be the resurrected bodies of Sir Keegan's murdered children, which potentially makes for a poignant, yet disturbing, moment.

Alternatively, if you're not keen on your players beating up child zombies, a second possibility is that the children still rest in their graves, and the zombies are the knights set to guard over their corpses. Although one has to again wonder where Sir Keegan found time to build coffins and set guards during his busy schedule of slaughtering every man, woman and child in the keep and then killing himself.

This is a nearly perfect encounter. It's mechanically sound, it's tactically interesting, it's clearly explained, it surprises the players without being unfair, it ties in to the backstory, and there's worthwhile treasure at the end of it in the form of a safewing amulet +1.


[1] Where did the Cube come from? The door into the area has been hastily boarded up and marked "Closed", but it's unclear whether this is hobgoblin work or an act of the keep's original inhabitants. The ecology of the Gelatinous Cube is something that does not bear much scrutiny.


Grant said...

I always assumed the cubes were installed to clean the place, eating all the dust and mould that would slowly build over time. They made the corridors 10 ft square to accomodate the cleaning cubes.

Anonymous said...

I guess that makes about as much sense as anything can when involving a big puddle of mobile jello.

GregT said...

That's a reasonable interpretation, especially for tomb installations that aren't intended to receive visitors. It's not so bright to install a man-eating monster as your cleaner in a facility currently in use, though.

Dan said...

Your comment about underground creatures having no reason to develop transparency, "as anything naturally living underground - won't be fooled by transparency" is well taken, but I don't think it applies here. In the world of D&D, there are plenty of darkvision and low-light-vision creatures (and races) that don't, as far as I know, see infrared traces, and would thus be tricked by the cube's near-invisibility. Not that I'm necessarily arguing that evolution must take place in D&D, but it does make sense given the other creatures in the D&D world. So don't be so hard on WotC!

Aside: I love this blog. I'm brand new to D&D, and I plan to DM a group of newbie friends through KotS. I was linked here a couple weeks ago from the Wikipedia article on KotS, and I've been a daily reader ever since.

Keep up the great work!

Rob G said...

I am disappointed that the Cube could even theoretically lose any sort of poll; Gelatinous Cubes are the best monster ever. They're totally ridiculous and totally awesome.

You might like this image:

Brog said...

One theory is that the cubes grow to fill the available space. So if you have ten-foot corridors, you get ten-foot cubes.

One does not like to imagine what would happen if a cube were ever to escape the dungeon..

Greg Tannahill said...

Brog: I'd forgotten that theory. Although one wonders why'd they'd hold to a cube shape were it not for specific evolution. Otherwise you'd get Gelatinous Oblongs filling entire passageways.

Dan: Thanks for the props, keep coming back!

Rob G: I lol'ed at your picture. And then slapped myself for unnecessary netspeak.

Anonymous said...

"Although one wonders why'd they'd hold to a cube shape were it not for specific evolution."
You'd have to assume their genetics insist on equal length sides.
I, too, am outraged that the cube is not winning the current poll.

"I always assumed the cubes were installed to clean the place"
I demand that this become the official explanation!

Anonymous said...

""I always assumed the cubes were installed to clean the place"
I demand that this become the official explanation!"

-- It was the official explanation for some version in the past. I remember reading in some earlier version d&d rulebook that cubes were created by "powerful magic users" to clean their towers/dungeons. At some point I think they stopped printing the link to powerful wizards so that DMs didn't feel they could only use cubes in places where wizards live/lived.