Completely real. I started a minecraft world with the seed Herobrine, spelled exactly as you see. The jump was strange, and I saw cow where two pigs were standing, A zombie fell on me and I died, And mined clay at the spawn point.
I eventually found more, I mined it and the game glitched. I was underwater and then sand holding a fishing rod. A spider attacked me, then I was damaged by the water itself. After dying I heard a chicken die. before this I saw sand floating.
Credit To: Keegan