Charles said he was instrumental in the development of Cosmo Kramer; he felt that "Jerry and George were so well-defined through Larry David and Jerry, that there was less room for me to, sort of, expand on those personas. But Kramer was very unformed at the beginning of the show and it gave me an area of creativity to, sort of, expand upon. So I spent a lot of time with Kramer because he was a character that I could have an impact on in the future of the show". It was Charles who imbued in Kramer a distrust of authority (especially in his episodes "The Baby Shower" and "The Heart Attack"), and who created the character of Kramer's notorious unseen friend Bob Sacamano, after his real-life friend of the same name.