The 26th President of the United States, Teddy Roosevelt, regularly staged boxing matches in the White House and took on anyone he could- including professional boxers.
Mike Tyson offered a zoo attendant $10,000 to let him fight a gorilla.
Hall of Fame boxer Sugar Ray Robinson backed out of a fight because he had a dream that he was going to kill his opponent in the ring. After a priest and minister convinced Robinson to fight, Robinson went into the ring and killed his opponent, Jimmy Doyle. Doyle was pushing himself to fight to “buy his mother a house, and after Doyle’s death in 1947, Robinson gave the earnings of his next four fights to Doyle’s mother, so she could buy that house.”