Dysfunctional Rules X: I Cast Comprehend Rules

[Beni-Kujaku]

What's about Trap the Soul?
Tarrasque would - what, "regrow" its soul?! Then what would happen when the gem is crushed? Tarrasque got one more soul?
(Yes, technically, Trap the Soul allows a save. But, even on a successful save, it still inflicts 4 negative levels - 12 shots later would get us 0 HD Tarasque...)

Cool Tarrasques say "no" to negative levels. Also, it's the Tarrasque. If it has to regrow a soul to avoid being killed, it will regrow a soul. Probably two or three, just to be sure. The Tarrasque does not die, unless with a Wish or Miracle. No air? The Tarrasque goes to 0, then -1 HP, but when it would die from suffocation with no save, its Regeneration just says no and nothing happens. Since the rules say nothing happens after the third round, the Tarrasque eventually naturally heals, and wakes up.
No food? The Tarrasque is dealt a lot of nonlethal damage, but since it can eat anything, it cannot truly starve unless in the vacuum of space, and something will eventually get in its mouth, at which point it immediately starts regenerating the nonlethal damage.
Instant, no-save death? Its ability says no. It didn't fail a save, so it isn't dealt 868 points of nonlethal damage, but also it is immune to death, so nothing happens.
Coup de Grace? Nonlethal damage.
Trap the Soul traps the material body as well as the soul, so it does not kill, and the Tarrasque is trapped.

[ShurikVch]

Trap the Soul traps the material body as well as the soul, so it does not kill, and the Tarrasque is trapped.

It doesn't:

The soulless body collapses in a mass of corruption and molders in a single round, reduced to dust.

Tarrasques say "no" to negative levels.

Not according to its description

[Jack_Simth]

Not according to its description

So you're looking at the Trap the Soul ability of the demilich rather than the Trap the Soul spell?

Because with the spell:

Trap the soul forces a creature’s life force (and its material body) into a gem. The gem holds the trapped entity indefinitely or until the gem is broken and the life force is released, which allows the material body to reform.

[ShurikVch]

So you're looking at the Trap the Soul ability of the demilich rather than the Trap the Soul spell?

Yes!
I never said "Trap the Soul spell"
And gave actual working link (not my fault nobody checked it)

[Jack_Simth]

Yes!
I never said "Trap the Soul spell"
And gave actual working link (not my fault nobody checked it)

Perhaps, but you also never really clarified when it became obvious what most thought you meant based on their objections.

[Beni-Kujaku]

Not according to its description

Oh‚ yeah‚ not the spell‚ okay. So yeah‚ it does not kill. Tarrasque says no to death. How does it work? Don't know. Either it regrows a soul or it lives on without one.

And the tarrasque has immunity to energy drain. I know there is some RAW reading that applying negative levels with an ability not specifically called energy drain would not be blocked‚ but I honestly think nobody thinks undead could be affected by any negative level that does not mention them.

[ShurikVch]

I honestly think nobody thinks undead could be affected by any negative level that does not mention them.

What - you mean Skeleton who trying to pick up the Holy Avenger wouldn't get -1 HD (and, thus, destroyed instantly for being 0 HD)?

Oh‚ yeah‚ not the spell‚ okay. So yeah‚ it does not kill. Tarrasque says no to death. How does it work? Don't know. Either it regrows a soul or it lives on without one.

How about the Trollbane?
It negates Regeneration
Few good hits - and Tarrasque goes down
Still no need for Wish or Miracle...

[Chronos]

Isn't Trollbane a poison? Big T is immune to those, too. But if you have something else that unconditionally shuts down regeneration like that, and isn't a poison (I think one of the Elder Evils has something?), then that does work, because the Tarrasque's "can't die" is part of its regeneration ability.

[ShurikVch]

Isn't Trollbane a poison? Big T is immune to those, too.

It's unclear: Trollbane is called "poison" only in the fluff text - despite missing all other attributes of poison (like save DC, or secondary damage)
Thus, "Yes or No" is up to DM
Still, I thought ahead in case of "Yes"

(I think one of the Elder Evils has something?)

Aspect of Sertrous got Poisoner's Breath, which suppresses any poison immunity

Also, Shaktari, Queen of Mariliths (Dragon #359) got Aura of Toxin, which not just suppressing poison immunities (other than those from "Con: -"), but even Delay Poison and Neutralize Poison spells! (but Shaktari is 30 HD - thus, more difficult to call than Aspect of Sertrous, which is 23 HD)

One more way to deal with poison immunity is to zap the Tarrasque with Trait Removal; but, if we using this spell, we can as well just remove the Regeneration...

[St Fan]

A minor one from Dragon Magazine #312, for the Fleshcrafter wizard variant:

Stitched Flesh Familiar: While other spellcasters summon familiars to do their bidding, the fleshcrafter forms his own. He can build a construct familiar with a value of 300 gp by gathering the necessary body parts from three Medium humanoids that he has killed, and making successful DC 18 Craft checks. He must then donate a portion of his own life force to grant his construct the spark of life. This portion of the process costs an additional 100 gp in components. (Failing the Craft check uses up this last 100 gp as well as any other wasted materials and money.) This shared life force creates such a deep bond between the two that the fleshcrafter cannot create another such familiar until his current servant dies.

It's interesting this class feature demands a Craft check... without specifying WHAT sub-category of the Craft skill is concerned. Where do you put your skill ranks to help this check?

[Tohron]

It's interesting this class feature demands a Craft check... without specifying WHAT sub-category of the Craft skill is concerned. Where do you put your skill ranks to help this check?

I guess the player can use a Craft sub-category of their choice - the only requirement is that it has to be a Craft check. It would be interesting to see a flesh familiar made with Craft(bowmaking).