Benedict Arnold is an American general who betrayed his country during the American Revolution, attempting to surrender a fort to the British and then later joining the side of the British. He is a villain in The Fairly Oddparents.
When Timmy Turner wishes The Founding Fathers into the future so he can interview them on TV for a history report, Benedict Arnold is able to trick John Hancock into signing "The Declaration of Surrenderpedence", causing the United States to lose the war and remain a British colony. This turns Dimmsdale in the future into a very British looking place. Luckily Timmy was able to get The Founding Fathers back to their time and prevent Bendict Arnold from tricking Hancock. He was then arrested after Jefferson exposed him.