Many of the shows/movies sometimes have a character which is the counterpart of a certain character. Both characters' appear in the same show/movie.
The bizarre character usually have stark similarities in terms of looks and habits with few behavioral differences. The bizarre character may or may not play the role of antagonist.
Here are some examples.
Friends: Russ vs. Ross
Seinfeld: Bizarro Jerry, George, Kramer vs. Real Jerry, George, Kramer
The Simpsons: Lester and Eliza vs. Bart and Lisa
Which was the first such bizarre/opposite character appearing in a movie/tv show? (along with the original character of course)