In Japan, and in the cartoons/movie, everyone calls him Koopa. But his 'other' name is Bowser, in America.
Nintendo of America calls him by his full name, which is King Bowser Koopa...his last name is Koopa and his first name is Bowser!
If this is so, then why did the movie/cartoons always refer to him as King Koopa? Were they calling him by his American last name, or were they calling him by his Japanese first name?