Help Build a Monster: Living Corrupted Spellpool

[Lormador]

Hello, playground denizens.

We need to make a crazy, corrupted Spellpool that will be a boss-level challenge for the following party.

1) 11th level Druid, very experienced player; traded animal companion for Turn Undead in this game
2) 9 Crusader / 1 Aegis / 1 Warblade; still a bit green (not using Stormguard + Thicket, etc)
3) Cohort: Rogue (Swashbuckler) 1 / Lore Warden 1 / Gifted Blade 4 / Elocator 1 / Shadowdancer 1

I am responsible for the cohort build. Yeah.... I'm that guy.

Background:
I'm DMing a Ravenloft campaign that's truly gone off the rails. It would be too involved for me to go into depth about how we got to this point, but right now we have the following (somewhat non-canon) situation. The time period of this is just prior to the Grand Conjunction, but I have my own interpretation of that (and anyway this isn't involved in the Conjunction plotline).

The Twisted Tower in the center of Teufeldorf (a small city) is (was?) the center of power for a cabal of dark magicians: dark magicians who had pooled their powers in a Spellpool.

The PCs mostly use this place to shop. It's located near the domain of Forlorn, and they spent the last 5 games inside Castle Tristenoira, finally solving everything and vanquishing the Darklord. Sacking this castle put them in possession of a Book of Vile Darkness (which, fun fact, is actually listed in the old 2nd edition boxed set as treasure for this adventure). Feeling that this was too valuable to just destroy, they Diplomanced their way to the highest Twisted Tower official they could find and started negotiating oh behalf of the "Freehold of Forfar." They got some concessions from Archmage Nicodemus and then went about the rest of their shopping, a process that took about a week in the town.

Having come into such a power source, Archmage Nicodemus determined that his station in the Twisted Tower was too humble for him. Not the wisest wizard in the tower, the coup turned out to be a little more than he could handle, and soon be found himself desperately thumbing through the darkest recesses of the tome for help. The demonic "help" that resulted turned out to be far too much for anyone to handle.

I'm not sure how I want to run the resulting situation, whether I want some Cabal mages holding some semblance of control over the Tower, whether I want to actually occupy it with a powerful demon and its thralls, or whether I want Archmage Nicodemus to survive in some form.

The only thing I'm sure of is that I want a crazy, corrupted Spellpool monster on the premises. The Living Spell template doesn't quite seem right for it. I turn to you, Giants, for advice.

[Uncle Pine]

Probably not exactly what you had in mind, but I'd suggest you to read that Angry GM article about the two headed two tailed bifurcated snake (/two orcs in one orc) and apply the same logic to your spellpool by making several living spells.

[Lormador]

That's a great idea.

It'll be easier for me to handle mechanically, less likely to just instantly kill whatever touches it, and more satisfying to battle. Plus oozes conform to the idea easily, and since it'll be huge anyway, perhaps they'll destroy the "middle" of the creature and even wind up with two separate oozes.

Maybe I'll just have this nasty thing in the tower for when they inevitably try to loot it.

EDIT: and if I make eight parts, one for each school of magic, the Spellpool will be somewhat organized.

[Darrin]

Probably not exactly what you had in mind, but I'd suggest you to read that Angry GM article about the two headed two tailed bifurcated snake (/two orcs in one orc) and apply the same logic to your spellpool by making several living spells.

I was going to say, "Just use a Teratomorph" (MM2), but this idea is much better.

[Lormador]

OK, I have drafted a monster that will work according to the ideas presented in the Angry GM articles, ideas that I'm not going to bother trying to explain much in the stat block. Living Spellpool of the Twisted Tower (Corrupted) CR ???
XP ???
Neutral Evil Gargantuan Ooze
Init +1; Senses Blindsight 60'; Perception +0 (usually irrelevant, see ooze traits)

Defense

AC 13/14/16; Touch 13/14/16; Flat-Footed 12/13/15; (-1 Large -2 Huge -4 Gargantuan +6 deflection +1 Dex)
HP 80 per partition (12d8+36 HD per partition)
Fort +13; Ref +11 Will +8
Defensive Abilities; DR 10/magic; SR 22

Offense

Speed 40'
Space 10 ft (each section); Reach 5 ft
Melee +12 Slam (1d6/1d8/2d6)+4 melee; or +12 melee touch [plus spell effects, see below]
or +12/+7 full attack
Ranged none
Special Attacks Engulf, Spell Effects (see text)

Statistics
Str 16, Dex 13, Con 16, Int 8, Wis 13, Cha 16
Base Atk +9; CMB 12+size [+1 Large, +2 Huge, +4 Gargantuan]; CMD 31+size (cannot be tripped or disarmed)
Feats none (mindless)
Skills none (mindless); Racial Modifiers N/A (no skills)
Languages none (mindless)
SQ Ooze traits (see below), Partition

Ooze Traits:
Blind (but have the blindsight special quality), with immunity to gaze attacks, visual effects, illusions, and other attack forms that rely on sight.
No Intelligence score, and immunity to all mind-affecting effects (charms, compulsions, phantasms, patterns, and morale effects). An ooze with an Intelligence score loses this trait.
Immunity to poison, sleep effects, paralysis, polymorph, and stunning.
Not subject to critical hits or flanking. Does not take additional damage from precision-based attacks, such as sneak attack.
Proficient with its natural weapons only.
Proficient with no armor.
Oozes eat and breathe, but do not sleep.

Partition: The Spellpool is six different Living Spell oozes (“partitions”), each made up of 4 Living Spells. Each partition rolls for initiative and takes actions separately. Each partition has a 10' space (being Large) and may overlap half of its space with another partition. When partitions are in physical contact with each other, they combine into a larger creature. 3+ partitions together make a Huge creature, and all 6 partitions together make a Gargantuan creature. This accounts for the different stats above. Combined partitions will be referred to as a “conglomerate” below.

Damage done to any conglomerate is divided equally among all of its member partitions. Each round, at the end of the last partition's turn, damage is redistributed (if some partitions were divided, took damage, and then recombined).

Each 20 damage that a partition sustains knocks out one of its spells, determined randomly. Partitions reduced to a single spell reflexively flee.

The partitions in this particular Living Spellpool consist in the following. Effects of saving throws are also given, failure on the left and success on the right.

Save D.C.s are 13+spell level

Partition A
Disintegrate (M)
Ball Lightning (M)
Fireball (L)
Web (M)

Partition B
Greater Dispel Magic (M)
Fear (S)
Lightning Bolt (L)
Glitterdust (M)

Partition C
Cloudkill (M)
Wall of Fire (M)
Sheet Lightning (M)
Sleep (M)

Partition D
Mind Fog (M)
Confusion (M)
Stinking Cloud (M)
Color Spray (S)

Partition E
Cone of Cold (M)
Black Tentacles (M)
Spiked Pit (M)
Burning Hands (S)

Partition F
Hold Monster (M)
Enervation (S)
Gust of Wind (M)
Grease (S)

Spell Effects
On its turn, each partition that successfully slams, touches, or engulfs an opponent subjects its victim to any 4 spell effects present in its conglomerate (if any).

Engulf (Ex): A living spell can flow around creatures that fit within its space as a standard action. It cannot make a slam attack during a round in which it engulfs. The living spell merely has to move over the opponents, affecting as many as it can cover. Opponents can make attacks of opportunity against the living spell, but if they do so they are not entitled to a saving throw. Those who do not attempt attacks of opportunity must succeed on a Reflex save (DC 10 + spell level + Cha modifier) or be engulfed; on a success, they are pushed back or aside (opponent's choice) as the spell moves forward. Engulfed creatures are subject to the full normal effect of the four spell(s) each round on the living spell's turn, and are considered to be grappled.

Creatures engulfed by a conglomerate are considered to be grappled by each partition participating in the conglomerate.

I'll probably need to put in some strong clues that the thing is very dangerous. I wouldn't want the PCs to just walk up to it as written. There's no way they'd survive the round.