In a late fifth season episode Bob is describing a school bully from his youth as having been nicknamed "Godzilla". This is quite amazing since the character of Godzilla did not appear until 1954 and, assuming Bob Hartley is roughly the same age as Bob Newhart, Hartley would have been around age 25 then; a little too old to still be in school.

Maybe Bob's bully got tagged that because he looked like a god-sized gorilla long before the Japanese character was thought of- and he didn't liked being called 'King Kong'