A year or so after the comic was produced they started collecting actual short stories based on this idea. And then they shopped it around, but were unable to sell it, as nobody would take on a book of short stories by largely unknown writers. So they self-published. And got it to number one on Amazon.*
And _then_ people started producing other stuff inspired by it.
Which leads me to the song I've been unable to get out of my head for the last few weeks, about the consequences of getting a slip with the word "Bear" on it.
Because since first watching this video, the phrase "And a Bear Came Out!" has come in useful far more often than you might ordinarily expect.
*More at http://machineofdeath.net/about
Original post on Dreamwidth - there are comments there.