Planar Transposition
Planar transposition is the High Science of Psychoportation. This powerful ability allows the psionicist to switch a portion of the Prime Material Plane for a portion of another plane. If the psionicist transposes his surroundings with one of the Inner (Elemental) Planes or the Ethereal or Astral Planes, the initial cost is 65 PSPs. If he actually summons a portion of an Outer Plane, the initial cost is 130 PSPs. The psionicist may attempt to switch a larger area than the normal 30-foot by 30-foot cube. For each additional 30-foot cube he attempts to transfer, he suffers a –1 penalty to his power score. The psionicist may instead transpose a donut-shaped ring 10 feet in diameter on the inside and 10 feet wide. The transposed planes remain switched for as long as the psionicist pays the maintenance cost.
The exact effects of this power are left to the DM, but some guidelines apply. Inanimate objects can be partially transposed, so a castle may be half in the Prime Material Plane with the psionicist and half in the Elemental Plane of Fire. However, living creatures are either all in or all out. If a creature wanders away from its transposed area into the new surroundings, it doesn’t return when the psionicist drops the power. Note that the psionicist may accidentally transpose an extraplaner creature when he grabs a chunk of its home plane and brings it to Athas.
The planes are not interrupted by their transposition; a piece of the Elemental Plane of Fire remains a roaring source of heat, transposing the base of a tower will not cause its top to fall, and so on. However, the new surroundings may affect the transposed areas eventually. A portion of Athas sent to the Plane of Magma would return a scorched wasteland.
Some possibilities with planar transposition include: creating a temporary oasis by transposing bare desert for a piece of the Elemental Plane of Water, opening a passage through a mountain by transposing a portion of the Ethereal Plane; sending a tower filled with enemy soldiers to the Abyss for a time (no telling what’ll he in it when the tower comes back… or hiding by surrounding oneself with a donut-shaped area of the Demiplane of Shadow or the Quasielemental Plane of Steam.
As noted above, planar transposition is a High Science. The psionicist cannot select this power as part of his normal advancement.