Consolidated PAO Infos
Change the Target of Polymorph any Object to 1 or more Objects!.
The following will count as a separate spell, with the simple name of Change Creature:
Duration is changed to Instantaneous by default. The spell cannot be dispelled in any way, nor undone except by another CC or by a Wish or Miracle spell with special requirements.
Casting time is increased to 24 hours, +24 per HD added and casting the spell takes the form of a ritual. Resting is permitted during the casting period.
You can do almost any change you like with the spell.
Want a few more arms?
Want wings?
Want a certain template?
Want to be another race? Become a monster?
The Change Creature spells effectively creates a new racial progression for a character or creature. It can also create Substitution Levels for existing class progressions, even retroactively. (Want to get rid of that third level of fighter?) Any character wishing to receive a casting of Change Creature must have XP to advance one level immediately, unless the change carries no HD cost, or only retroactively creates a sub-level.
If the change carries a HD cost the character then advances with the first HD of the new progression immediately, and from then on can decide at any level to advance either a class level or a level of his creature progression.
Some possible changes:
A pair of limbs (arms, legs) will add one RHD and carry a minor stat boost of +2 to Str OR Dex.
Wings that grant double-land/average will cost 5000XP, unless you want special abilities like faster flight, better maneuverability, etc.
A template will add it's increase in CR+n, where n is anything from 0 to 3, depending on the template. Some templates lack LA but DO advance CR, I'm not sure about those, yet. Some templates offer worlds of suck for huge cost, basically I'll probably give you discounts on those, should you want them. Other templates give worlds of win for negligable cost, so you can probably expect n to be rather approaching 3 than 1.
Changing your race will add the new races LA in HD+n, and obviously change your type, etc. Existing RHD won't normally be recalculated, although you have the option of doing that for an added cost.
Turning into a monster will add the monsters CR+n in HD. You can give up class-levels to accomodate the RHD, and of course you will need to have sufficient total HD to allow the change.
Increasing your size in the range of an "Enlarge Person" spell will add the same bonuses as the spell, and cost 1RHD. Increasing your size further will gain benefits as the Giant Size spell and cost 1HD/size category +1. Obviously being colossal isn't always advantageous.
If you change yourself too much you should probably become an Aberration, although you will receive warning of this before the change, and will probably be able to do something about it.
Adding Spell-like abilities equivalent to the "Spell-stitched" template (but no other bonuses) adds one RHD. You must have sufficient HD to meet caster-level requirements of spells with your CL of HD-1, but this change acts like a scaling template, so you can get it early and automatically receive the benefits later.
Adding an at-will SLA of up to 6th level will cost 2RHD and offer a CL of HD-2.
All SLAs have a casting time as the spell, metamagic is possible. Special material components must still be provided. You must pay 10 times the average XP-cost of the spell during the PAO ritual, after that XP costs are no longer required.
All changes will have a roleplaying requirement, a gold cost, and also require special ingredients. I expect you to hold your own measure with this spell.
Racial HD will get some changes:
Dragon HD advance arcane CL
Aberration HD advance Psionics CL
Undead HD generally advance casting and Psionics CL
Outsider HD advance arcane OR divine CL
Human HD get an increase in the number of class skills and skills/lvl, and advance arcane or divine or psionics CL
Monstrous Humanoid HD are advanced to D10s and advance Initiator-level
Fey HD advance arcane CL
Giant HD gain full BAB and are advanced to D12s, OR stay with 3/4 BAB and advance divine casting.
Elemental HD advance Arcane or Divine CL
Magical Beast HD advance Arcane or Divine CL
Plant HD advance divine CL
I have ignored mindless types. This will necessitate reworking some monsters, but that is paperwork that is largely my own. My focus probably won't be on monsters, anyway, in this campaign.
Now granting all those possibilities is pretty hard if you hard-wire all the rules. If you have a special wish that will make the game considerably more fun for you I don't see special reasons to deny it. I will, however, request final say on all changes made. Also, I want to specifically boost non-casters with these possibilities. Pre-epic I primarily see them as recipients of this spell. Also, the possibilities and costs reflect the basic premise that Class-features > than everything else. The fact that this is not always so doesn't particularly speak for the WOTC writers. However, it is your responsibility to make sure you get sufficient gain for your class-levels.