Phantasmal Stench: As we are all aware, convention attendees have worked long and hard to change their behavior in the face of stereotypes of them as unwashed, smelly and disgusting. If you poll con attendees, they'll all tell you that of course they shower and change their clothes every day of the convention. So why, then, in the face of all these truthful and hygenic conventioneers, do we still catch a distinctive and unpleasant scent of human body odor?
The answer, of course, is that the stench has endured for so long that it is now self-perpetuating and sentient. The sheer amount of body odor pumped into the air at cons over the years has created an intelligent stink--one whose personality is naturally formed from hundreds of con attendees, and which therefore loves to hang out at cons. It particularly loves the dealer rooms; even though it has no money, it likes to "window shop". It also enjoys hanging out at gaming sessions and all-night anime rooms.
If you find yourself walking through a pocket of the phantasmal stench, simply breathe through your mouth and mutter that you think you saw a bootleg copy of the 'Dungeons and Dragons' cartoon on the other side of the dealer room. (The phantasmal stench loves that show.)