Nelson Mandela Muntz is a fictional character and the lead school bully from the animated TV series The Simpsons. He is voiced by Nancy Cartwright. Nelson was introduced in Season 1's "Bart the General" as an antagonist but later turned into one of Bart Simpson's best friends. He is well known for his signature laugh "Haw Haw!"
Nelson is a student and bully at Springfield Elementary School. He is known to have terrorized virtually every kid in Springfield at one point or another. Most often, however, it is the school nerds and less popular students, such as Milhouse and Martin, who are the subject of his cruelty. Nelson shows the occasional glimpse of humanity, though, and other characters have occasionally warmed to him; Lisa dates him briefly in "Lisa's Date with Density", Marge informally adopts him in "Sleeping with the Enemy", and Bart is shown as a friend to him several times, such as in "The Haw-Hawed Couple". His family life is dysfunctional. While some early episodes offer inconsistent histories (such as Nelson's dad going insane and abandoning him, Nelson's parents divorcing because of his mom's cough drop addiction, or Nelson's dad in prison while his mom "has bigger problems"), the canon story that has evolved is that he lives in a dilapidated house with his mother who works on the fringes of the sex industry, either as a waitress at Hooters or in a topless bar. The character design and voice portrayal of both parents has varied throughout the course of the series.