How about something about taking hallucinogenics and gaining a save bonus versus illusions/chance of automatically seeing through illusions? You're just so damn used to tripping balls, the line between reality and fiction is exceptionally clear.
That would have to have a reeeeally odd prerequisite.
Maybe something about regulating body temperature to get an effect similar to Endure Elements?
Hmm, that has potential. Needing ranks in Autohypnosis. I like it.