Building GLaDOS

[Tvtyrant]

Portal 2 finally fell to a price I was willing to pay, and now after my second play through I am inspired to make a living dungeon like GLaDOS.

So far my concept is a large underground bunker that has been affected by a Animate Object spell (permanent) and an Awaken Construct spell. The bunker is actually made up of two separate parts; the awakened interior walls which are coated in wires, and outer walls that are made of panels and can be rearranged by the wires (which act like tentacles). The reason for building it this way is that an animated object does not have a large amount of health, so the creator is protecting it by effectively disguising it.

On the other hand, there might be a better way to do this, so I would like some suggestions!

[Feralventas]

Craft Golem. No seriously, Craft Golem. Animating constructs will require a hell of a lot to be done, but building one, giant golem the size of a complex, while a much more taxing task, will result in something much more along the lines of what you're looking for. The difficulty will be in developing the creature's perceptions, maybe even going as far as to give it enough divine rank to scry on itself as per the divine ability related to such (Check 3.5's Deities and Demigods for details.) This way the golem can control all of the moving pieces inside itself, can see anywhere within itself and outside (though not both at the same time, perhaps) and have all the time in the world to conduct whatever mad schemes it may have.

You will be looking at some epic-level construction in this, however, so make sure you're prepared to have that sort of thing as part of your setting.

[Zerter]

Assuming you are the DM: just write down what you want and it is done. No need to feel hindered by the lack of HP or turn to the mess that is epic level.

[Psyren]

In D&D terms, she needs to have total or near-total control over the player's surroundings to enforce their feelings of isolation and heighten the sense of danger. The best way to do that would be to make her a living plane (there is an example one in MotP 154, but it's too "squishy" to be GLaDOS imo, so some tweaking would be needed.) This would allow her to alter the landscape as needed, create the various turrets and other puzzle devices to challenge the players, and finally prevent the players from simply plane-shifting or teleporting away once you trap them.

A Genius Loci is another idea but the "never talking directly" doesn't fit GLaDOS at all.

[Urpriest]

I'd at least take a glance at the stats of the Living Vault (ELH), a similar concept if not as dungeon-ready.

Also, traps are magic items, and any magic item can be made into an intelligent item. While you might want a few animated objects, the traps will be more versatile.

[supermonkeyjoe]

Try looking into the Dungeon Lord PrC in Dungeonscape, it allows a creature to do all kinds of nifty things in its designated dungeon like knowing everything that happens inside it, opening/closing doors, teleporting around and animating objects.

[Tvtyrant]

@Zerter: While it is certainly true that I can do that, I prefer to stick within the rules as much as possible. I decided to stick to this route early on when my players wanted to make their own flying castle after destroying a Lich's, and I had simply thrown one together. If I did make a living dungeon from scratch, I would have to make it so that they can.

The Living Vault and Living Plane look pretty close to what I want. The sentient traps are also pretty good (my plan was to have the dungeon recycle traps by moving them from room to room, making it appear that the dungeon was large and full of stuff while it was really only a few dozen rooms.)

[eggs]

I really want to find a way to get a Haunt Shift hivemind happening. (Damn those Mind Effect tags!)

[Reluctance]

Let me second the idea of having it be a sentient plane. This gives you a lot more control, and actually requires less plot handwaving than having a huge underground bunker built for no real purpose. The purpose for going to the plane is to find the wizard that did it. ("Did it" in this case meaning casting the initial Genesis. The fact that he imbued his consciousness into the plane instead of just hanging out there is unknown at this point.)

I'll also warn you that Portal maps very poorly to D&D. Sure, you can give the intelligence of the plane a testing fetish. One is a game of spacial reasoning, the other is a game of resource management and turn-based combat. Individual traps can be handled with existing trap mechanics, with the usual caveats about trap overuse slowing down play and/or becoming a HP tax.

And if the PCs really want to become planes? Call it an incantation. Say that it requires the caster's mind and soul to be bound to the purpose. You'd then be well within your rights to insist that becoming an adventure site does mean retiring the character.

[Tvtyrant]

I find your points persuasive, and I was never planning on running it like an Aperture Science game. My primary interest was in the living dungeon aspect, which seems to be best done from the point of a Living Plane.

As for traps, remember that summon monster traps also exist, and can be made to make infinite monsters (although only as many as the CL to turns allows at any one time). You can make different sized and typed ambushes by moving monsters from different traps together.