"Lloyd Changes His Mind" is the fifteenth episode of Lloyd in Space.
Lloyd is sick and tired of Francine always reading his mind. To fix this problem, Douglas gives him a prototype mind scrambler which can theoretically block that. Unfortunately, when Francine tries to read Lloyd's mind with the helmet on, there's an unfortunate side effect - they switch bodies! At first Francine likes being in Lloyd's body, but when she sees how hard it is to be a teenager, she wants to switch back. At that point however, Lloyd has gotten used to the easy life of a preschooler and doesn't want to. But when he finds out that Francine (in his body) is sent on a field trip to see an eclipse on Darkon 5, where there'll be total darkness, which Francine is deathly afraid of, he sets out to save her. Will he succeed?