Annabelle Oleson was the sister of Nels Oleson, she worked in the circus as a sideshow attraction.
In Nels youth he was quite ashamed of Annabelle, due to her weight, and would get to the school house as early as possible so he would not be seen with her, Annabelle knew this. She joined the circus and was greatly loved by everyone. She loved himself and considered that her life had meaning and enjoyed making people laugh. Later, Nels apologized to Annabelle and was no longer afraid to admit that she was his sister. (Episode 605: Annabelle)