Pilpin's Soul Exchange
(Alteration, Necromancy)

Range:  0
Components:  V, S, M
Duration:  Permanent until wizard reverses
Casting Time:  1 turn
Area of Effect:  Two creatures touched
Saving Throw:  Special

This spell causes the life forces of two creatures to exchange. The wizard must touch both creatures simultaneously at the end of casting without having to make a to-hit roll. Any two creatures with a soul or spirit (eg., humans, elves, animals, birds, dragons, fish, etc.) can be affected. Examples of creatures that do not have souls or spirits (as we understand them) are: undead, demons, devils, automatons such as golems, and extra-planar creatures in general.
The saving throw against Pilpin's soul exchange depends on whether both, one, or neither of the recipients are willing to undergo the exchange. Treat indifferent as unwilling. If both recipients are willing, no saving throw is required. If one recipient is willing but the other is not, then the unwilling target is allowed a saving throw with a -2 penalty. If both are unwilling, then they are both allowed a normal saving throw. A successful saving throw by any one of the recipients negates the spell.
This spell is much more powerful when used in combination with the 8th-level trap the soul. Unwilling creatures that are trapped within a gem prison have an additional -6 penalty on their saving throw. So if one recipient is willing and the other not, and the unwilling recipient is first imprisoned by trap the soul, the unwilling creature saves with a -8 penalty. If both recipients are unwilling and trapped in gem prisons, they both save with a -6 penalty. The spell does not release them from the gem prisons, only exchanges their souls.
A creature's soul in a different body has that body's hit points or Hit Dice, Strength, Dexterity, Constitution, and Comeliness, but the soul's Intelligence, Wisdom, Charisma (modified by the body's new Comeliness), memories, and Intelligence based skills (languages, nonweapon proficiencies, spellcasting ability, etc.). The non-physical abilities can be used only if the body has the required physical attributes. If the body has extraordinary Strength, it can only be used if a warrior's soul enters the body. The body will not radiate magic. The alignment will be that of the soul. True seeing will reveal to a person that previously knew the recipient of the soul exchange that it is no longer the same person.
The spell can only be reversed by a carefully worded and executed wish (creatures must be touching each other), another soul exchange, or the will of the original wizard. If a creature dies while in another's body, it can only be brought back with its own body, so if both creatures died this could be a reckless way to reverse the spell. The material components are a diamond worth 1000 gp and a bit of fresh brain tissue from a mind flayer (not necessarily freshly acquired, possibly magically preserved).

