A story told on the internet, about real life, that turns out to be fiction. Comes from the website www.bash.org, a site listing humorous logs of IRC conversations. A common theme is that of a user telling a story of how his building is burning down, the joke being that he had to tell his friends on the internet about it before running for his life.
"You know that story Jim's always telling, about the woman he slept with that ended up being his buddie's mom? Turns out it's just a bash fire."