Gregor Clegane (Earth-6120)

"I'd be a bloody fool if he didn't frighten me. He's freakish big and freakish strong. And quicker than you'd expect for a man of that size."

- Bronn

Ser Gregor Clegane was a knight of House Clegane, the older brother of Sandor Clegane, and a notoriously fearsome, extremely lethal and much-feared warrior, with a tendency toward extreme and excessive violence. Due to his incredibly massive size, he was called "The Mountain That Rides" or more often simply "The Mountain."

Source

 * https://gameofthrones.fandom.com/wiki/Gregor_Clegane