Longcat is a real cat (obviously). For some reason when Longcat's uninspired owners named him, they must have overlooked the extremely fucking huge length of the kitten, and they named him after his second most defining feature. Therefore Longcat's real name is Shiroi (白い), which means "white" in Japanese. This may, however, be an azn mind game to confuse black people who believe they are the longest members of the human species.

One day, there was a picture of a cat. It was not Caturday but this specific cat was so long it became a meme and, though the day was not specifically the day of cats, this cat's length became famous. Originating from 2ch, it is a sacred meme that embodies the spirit of the lulz, as it has touched the hearts of every anon and /b/tard in the internets. All attempts made by faggots who desire to steal it from anon have earned the swift, unmerciful wrath of the Internet Hate Machine.