Fedor Emelianenko.
The best heavyweight MMA fighter in the world. He has never been defeated in 33 fights. His one recorded loss was a cut from an illegal elbow that was only ruled a loss (and not a DQ in his favour) because of the tournament structure.
He shows no emotion of any kind before, during, or after fighting. He walks in, doesn't look you in the eye, then he either knocks you out or submits you.
He reacts to his big wins with less excitement than you or I would if we found a really good parking space.
And he doesn't give a damn that he's famous. He avoids publicity and disappears back to Russia between fights.
Fear him, ladies and gentlemen.
Fear him.