Pun-Pun can grant himself an ability as innocent as:
Tough it Out:
Benefit: If Pun-Pun would go unconscious due to any effect, he instead remains conscious.
Or, he could grant himself an ability as powerful as:
I Win:
Benefit: Pun-Pun cannot be harmed, directly or indirectly. Any act that would harm him automatically fails, at any place and at any given time. Further, Pun-Pun automatically succeeds at anything he attempts.
Given this level of power with Manipulate Form, it would be easy to say he can do anything and no one can stop him. Generally though, I (and most everyone else that has participated in this exercise) do not use this power of Manipulate Form. It is much more fun to stay within the abilities found in the rulebooks, and doing so allows others to challenge Pun-Pun with a sliver of a chance .
LordofProcrastination devised an interesting way to justify out of the ordinary abilities without simply conjuring them from thin air. 'Out of the ordinary abilities' is referring to abilities that would normally be found as supernatural or spell-like but instead granted to Pun-Pun as extraordinary.
For example, Manipulate Form is normally a supernatural ability. However, Pun-Pun could easily stay within the parameters set by Manipulate Form and grant himself an extraordinary version of Manipulate Form. The benefit being that Pun-Pun can make himself completely immune to all magic and supernatural effects without hindering the use of his own Manipulate Form ability.
This is all too easy though, so LordofProcrastination used the Epic Spell rules in the Epic Level Handbook to create a clever workaround. Here is the low down:
Okay, here's a little combo that will help clarify things even more for Pun-Pun. In particular, it will allow for the diversification of his abilities and get past some of the inherent rancor to the "sheer player-invention" aspect of Manipulate Form.
Premise 1: Pun-Pun has access to Epic Spellcasting, and can create any pretty much Epic Spell he imagines.
Premise 2: The Conjure, Fortify, and Life seeds can be used in conjunction to create entirely new creatures. Furthermore, these creatures can be given abilities based on any epic seed added which "replicates the desired ability." Whether these abilities are spell-like, supernatural, or extraordinary is up to the creator of the spell.
Premise 3: The Shadow Seed can replicate any spell and any individual. The Transform seed can reproduce any creature/creature's abilities. The Ward Seed can produce immunity to any and all spells. The Reflect Seed offers protection from all ranged, melee, and spell-like attacks. And so on and so forth.
Conclusion: Pun-Pun can create creatures with pretty much any ability, spell, or feature in any mode he desires, which can then be gained through the old Manipulate Form trick. Getting an (Ex) Manipulate Form ability should be first on the list, which would then mean that there's no worrying about gaining total magical immunity. Furthermore, this means that Pun-Pun no longer has to rely on active spells (epic or not), they can all be incorporated into himself as extraordinary (that is, non-magical) abilities of any duration/method of activation desired.