Person on a ship starts showing up to work on an invisible motorcycle. Everwhere he goes, before he leaves, he hops on his invisible motorcycle, revs it up, and mimes riding the bike to his next destination. He is always normal otherwise, going about his daily job as if nothing's wrong. If asked, he merely says "this is my bike" and won't discuss it further. Eventually he's given a psychiatric evaluation and is deemed mentally icompetent to serve. As he's "driving" off the ship for the last time with his discharge papers in his hand, he hops off his bike at the brow (entrance/exit of the ship), turns off the ignition, salutes the bike and says "I don't need this anymore," and walks off the ship forever. Then he goes here; http://www.patriotfiles.com/hs.pps