Dora Winifred Read MacDonald is Arthur's sister. She whines a lot, tries to annoy Arthur to death, and endorsed Mary Moocow for president in 2012. She recently admitted to having caused the blackout at the 2013 Super Bowl, and to having hacked Sesame Street's YouTube account. She also assassinated Bionic Bunny, and was the one who put too much mustard in the cure for AIDS.