What rules effects, if any, would converting the ability of psionics itself to a supernatural ability have?

Question

Related to this answer wherein it is demonstrated that "the ability to manifest psionic powers is a psi-like ability".

Also from the SRD, which seems to establish that Psi-like equals Spell-like:

Psi-Like Abilities And Feats Creatures with access to psi-like abilities can use the feats Empower Spell-Like Ability and Quicken Spell-Like Ability.

These feats can be used only on psi-like abilities that do not have increased effects due to augmentation. Furthermore, the creature can empower only a psi-like ability with a level less than or equal to half its manifester level (round down) minus 2, and can quicken only a psi-like ability with a level less than or equal to half its manifester level (round down) minus 4.

Creatures With “Psionics” Entries Psionic monsters often possess spell-like abilities that are identified as “psionics,” instead of “spell-like abilities.” For all intents and purposes, creatures with spell-like abilities described as psionics are considered to possess psi-like abilities, and they manifest their powers as described above.

And finally, from Savage Species:

Supernatural Transformation

You convert a spell-like ability to a supernatural ability.

Prerequisite: Innate spell-like ability.

Benefit: One of your innate spell-like abilities becomes a supernatural ability. It is no longer subject to spell resistance, though it can still be suppressed in an antimagic field. Using this ability does not provoke an attack of opportunity. The number of uses, if limited, does not change. The effective caster level equals your total Hit Dice or the effective caster level of the original ability, whichever is higher.

Special: You can gain this feat multiple times. Its effects do not stack. Each time you take it, it applies to a new spell-like ability

Thus, the question: what rules effects, if any, would converting the ability of manifesting psionic powers itself to a supernatural ability have?

Answer 1

Luckily, we don’t have to worry about this, because manifesting isn’t innate as required by Supernatural Transformation. What exactly “innate” means is honestly rather unclear, but considering what Savage Species is, “based on your race or the sort of creature you are” is overwhelmingly likely, so class-based stuff like manifesting isn’t.

...unless you’re a gem dragon. You’re going to make me consider gem dragons, aren’t you?

_{Freaking dragons, always ruining things...}

Anyway, the short answer is, we do not and cannot know. What exactly it means for psionic manifesting to “be a psi-like ability” is really ambiguous, and none of the apparent options really makes all that much sense. Is each and every power a separate psi-like ability? Uh, maybe, but that seems weird when it seems to be calling out the ability to manifest in the first place as “a” psi-like ability. Is the ability to manifest powers somehow a constant, permanent effect of a psi-like ability? I sure hope not, since that implies it could get dispelled (!). Is each and every power you manifest somehow a different variation on one solitary psi-like ability? That seems utterly bizarre and implies that stuff that has you choose a psi-like ability would allow you to choose “all of your manifesting ever,” which uh, to put it mildly, would be overpowered.

Ultimately, something becoming supernatural means it no longer provokes attacks of opportunity, never require Concentration, cannot be counterspelled, ignores spell (power) resistance, and cannot be dispelled. All-in-all, quite good. Which is why Supernatural Transformation is a horribly-broken feat even when you can’t just apply it to all your manifesting ever.

So basically, I don’t know, and I’m quite sure that no one else knows either, but I can tell you that, pretty much no matter what it does, you shouldn’t allow it in your game.

_{Dragons, man, we should just ban those altogether... would fix a lot of problems...}

Answer 2

It's Complicated

The Supernatural Transformation feat^{(Savage Species, p39)} transforms psionic manifesting ability into being much harder to disrupt or counter for those creatures who manifest innately, but doesn't remove the cost of using powers, where those costs exist. It also sets the minimum manifester level up to the creature's total Hit Dice, which can be quite nice for some creatures.

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The issue here is that, as both the SRD, and Expanded Psionics Handbook each say:

The manifestation of powers by a psionic character is considered a psi-like ability, as is the manifestation of powers by creatures without a psionic class (creatures with the psionic subtype, also simply called psionic creatures).

This suggests that using psionics at all is a psi-like ability. However, the same section goes on to say:

Psi-like abilities have no verbal, somatic, or material components, nor do they require a focus or have an XP cost (even if the equivalent power has an XP cost). The user activates them mentally. Armor never affects a psi-like ability’s use. A psi-like ability has a manifesting time of 1 standard action unless noted otherwise in the ability description. In all other ways, a psi-like ability functions just like a power. However, a psionic creature does not have to pay a psi-like ability’s power point cost.

These rules seem ambiguously contradictory. The first section refers to 'the manifestation of powers' plural. A psion's manifesting ability is a psi-like ability. As is the ability of a psionic human with the Hidden Talent feat^{(XPH, 67)} to manifest a 1st level psionic power. But both those abilities require power points and all the other costs associated with the powers they manifest. Only for abilities explicitly listed individually or en-masse as psi-like abilities do creatures not pay power point or XP costs.

The unbodied entry states that it has:

Psionic Powers: An unbodied manifests powers as a 4th-level psion (telepath). The save DCs are Intelligence-based. [...]An unbodied who takes levels in psion (telepath) adds its racial manifesting ability and psion levels together to determine its power point reserve, manifester level, and powers known.

The unbodied pays power points for these powers, is subject to dispelling and attacks of opportunity for using them, just as a psion is, as that's what they're equivalent to.

The psion's ability to manifest is definitely not innate, but from its class. The Hidden talent Human's feat, on the other hand might just be considered to be innate, especially as the feat can only be taken at 1st level. The unbodied's manifesting would definitely be innate, as it's racial.

What would be the effect of the feat on the psion's manifesting? Nothing, as it's ineligible.

What about on the Hidden Talent Human's power? This is a gray area, but I'd like to rule that its ability becomes supernatural. It still costs power points, and possibly XP, to manifest, but the Hidden Talent's manifester level for the power now equals it's total HD, and it's using a power that can't be disrupted, dispelled or negated.

The same happens to the manifesting ability of the unbodied; it uses power points, and XP as necessary, to manifest the powers, but the effects can't be dispelled or negated, and don't provoke attacks of opportunity. However, the manifesting ability that it might gain from psion (telepath) class levels would still be subject to those things; it's only the 4th level manifesting ability that the Supernatural Transformation feat affects, as that's all that's innate. If it takes other classes, which don't increase manifester level, then it's ML would still equal total HD.

Answer 3

Disregarding issues of legality which have been addressed by other answers, having manifesting be a Supernatural ability would carry the following rather powerful implications:

1. Powers are no longer dispellable.
2. They are no longer subject to Power/Spell resistance.
3. They no longer carry XP costs.

This eliminates whole swaths of balancing costs certain powers rely on. Powers like Change Fate, Timeless Body, Time Regression, Psychic Chirurgery, Reality Revision, etc. become literally brokenly good.