Herobrine?

I never believed in Herobrine.
The story of him all seem like a hoax
Today I decided to play single player
Level name: Herobrine
Level seed: herobrineliveshere
Again expecting no results I was shocked when a strange mob appeared
This mob had bright white eyes and spawned when I turned the fog all the way down
To get a believable screenshot I had to turn the fog down
but has soon has the fog distance when to its max he despawned
I couldn't believe my eyes what I seen.
Being a rational thinker I quickly checked my bin folder and my world saves for ANY sign of any new mob on this world
I could find nothing.
I later got distracted while on the same world and left my minecraft client up while i visited my friend
I was at my friends house for 3 hours when I got back on my world later everything was the same
Then that's when I turned down my fog once more just out of a habit of pressing "F"
He spawned again only this time he was hostile
he chased me up and down a hillside
he was faster
I got one shot before he led me on this chase