Ghost-Warped (3.5e Trait)
From D&D Wiki
Your body reacts strangely to contact with ghosts and other incorporeal creatures, granting you some of their disabilities for a short time.
Benefit: The first time in an encounter when you take damage from an incorporeal attack, you must make a Fortitude save (DC 12+1/2 the creature's HD) or have a part of your body become incorporeal. Roll a d6 to determine the effected body part: 1-2 hands, 3-4 feet, or 5-6 body. If your hands are affected, you lose the ability to manipulate objects with them, but you gain an incorporeal touch attack that deals the same damage as your unarmed strikes plus 1/2 your Charisma modifier. If your feet are affected your land speed drops to 10 feet, but you also gain the affects of the feather fall spell. If your body is affected, you take a -4 penalty to Armor Class against corporeal attacks, but gain a +4 bonus to Armor Class against incorporeal attacks.
Drawback: No matter what the effect, it goes away after 2d4 rounds, after which you are staggered for 1 round.