From what I can tell the purple neko monster pics were spawned off Purple Bonus. They apparently were a big hit and got 2Carat/Taoyan
http://taoyan2carat.hp.infoseek.co.jp/top.html (enter at your own risk) involved. I believe Darkkaminari mentions being inspired by Purple Bonus' pics. From there 4chan's /d has been happy to make sure the pics keep in circulation. There was apparently an English fan-fiction based off these pics. Apparently it was an on-going affair that actually managed to get its own internet drama thus forcing the authors to moved it to a secluded group someplace with invite only. From what I've heard its not worth looking for.