Ms. Blank

Ms. Blank was an unseen substitute teacher for Mr. Ratburn's class, mentioned during a flashback in Arthur's Substitute Teacher Trouble. She was unable to show up for class, and instead Miss Sweetwater was being the substitute teacher in the classroom who let the class color and have snacks.

Trivia

 * Miss Blank is likely only a joke on part of the writers, her last name being a reference to the fact that she was never actually seen onscreen at any point in the show, leaving her true existence rather ambiguous.