Herobrine, also known as “HIM”, is a mysterious character from a Minecraft creepypasta story. He is portrayed as a non-player character in single-player Minecraft with the default skin and completely white eyes.
IGN reported that the first posting of the original creepypasta story was on the Minecraft forums.
"Herobrine began as a single, foggy screenshot of a distant figure posted on the Minecraft forums. The picture was accompanied by the story of a Minecraft player finding strange, unexplained constructions in their world, apparently the sign of someone or something else being present"-Minecraft Forums
The earliest known thread on the Minecraft forums that mentions Herobrine was posted on August 30th, 2010.