Homer Simpson; Marge Simpson; Bart Simpson; Lisa Simpson; Maggie Simpson; Nelson Muntz; Moe Szyslak; Milhouse Van Houten; Martin Prince; Wendell; Ralph Wiggum; Carl; Lenny; Dr. Julius Hibbert; Gil; Ned Flanders; Reverend Lovejoy; Snake; Barney Gumble; Sherri; Terri; Uter; Principal Skinner; Groundskeeper Willie MacMoran; Dolph; Jimbo Jones; Kearney; Database; Lunchlady Doris
Synopsis
Lisa is diagnosed with complications due to Middle Child Syndrome, so the Simpsons adopt Nelson Muntz to balance things out. But Nelson soon becomes head of the household and Homer suffers from Displaced Dad Syndrome.