There are some cases where an incorporeal creature will become corporeal or is able to interact as if corporeal. The Assume Likeness ability of the Psion Uncarnate(1) (an unbodied(2) has an ability with same name and effect), says that you can change to look like any Small to Large creature, with no change in abilities, while incorporeal, but not what happens if you're no longer incorporeal while the ability is in effect, nor what would happen if you were able to be conditionally corporeal.
If a Psion Uncarnate were using Assume Likeness to look like a creature noticeably different from its original form, say a unicorn (no hands), an ogre (hands, but large size), or an animated armoire (very unusual shape) were to become corporeal, through a ghost trap spell(3) or simply ending the Shed Body ability, or was able to affect objects as if corporeal through the ghostly grasp feat(4), would he use his original form, or that of the assumed likeness?
- Expanded Psionics Handbook, p. 148
- Expanded Psionics Handbook, p. 216
- Spell Compendium, p. 103
- Libris Mortis, p. 27