You are plagued by an irrational fear of something. Every time you are confronted with your inner fear, you must make a check using this trait as a modifier against a DC set by the Keeper, depending on the situation, such as your chance to escape or avoid the fearing object.
On anything less than a successful check, you will flee in panic from the object or situation or if you cannot flee, you will crawl up in a corner unable to act as you are paralyzed by fear. The fear object should be something that is possible to happen.