One man was one of the most iconoclastic and controversial actors of the 20th century — the other was the voice of Underdog on a Saturday morning cartoon show. But once they met on an Illinois schoolyard, nine-year-olds Marlon Brando and Wally Cox became lifelong friends — and even lovers, according to some accounts. We look at each man’s career and their private, intense connection — one that endured even after Cox’s death in 1973.