Herobrine is a rumored mob to be seen in Minecraft possessing a similar appearance to Steve, with the exception of his glowing white eyes. His behavior is limited to corruption of the worlds, which is demonstrated by the presence of any structures that cannot be generated naturally in Minecraft and were not created by the player. Since he never existed in Vanilla Minecraft, spawning him in an unmodded version of the game is impossible.
He is a creepypasta or horror story/urban legend that has been cooked up by the massive community of Minecraft fans. Herobrine’s mentions go back to 2010 when a couple of Minecraft players claimed to have seen Herobrine haunting their single-player worlds.
One Minecraft player even posted an unclear screenshot of what looked like Herobrine - basically Steve with glowing white eyes. And thus, began the legend of Herobrine, which eventually became a story that everyone wanted to be a part of!
Herobrine corrupted the worlds of Minecraft players, by stealing items, cutting down the leaves in forests, or by mining 2 × 2 tunnels in caves. Eventually, Herobrine came to be known as a Minecraft community symbol, adapted into skins, mods, and meme material.