The concept of "rainbow vomit" stems from a blog article on I-mockery about visiting Little Tokyo neighborhood in LA, posted by the site owner RoG on August 6th, 2006. In reviewing the Japanese supermarket, RoG commented on the colorful packagings of Japanese snacks found in the store to be like a rainbow threw-up all over their snack section and forever stained the packages with a million bright colors. From there users started to create their own images. Now you can use it whenever you want!