In his first appearance on The Simpsons, Waylon Smithers looked to join the ranks of Carl and Julius Hibbert as one of the few black characters on the show. In his next appearance, however, Smithers was suddenly white. There are a couple of different explanations for Smithers' shifting race, which change depending on who you ask. Some writers claim that the character was originally intended to be black, but they changed their minds when they saw how subservient a role Smithers would play. Others who worked on the first season claim that it was simply an animation mistake.
Waylon Smithers Is Black and Then He Isn't