At one time during the strip shown in the book collection "The Revenge of the Babysat", Calvin's parents prepare to go out on a night with a dinner and a movie while leaving Calvin with Rosalyn. When he finds out she is coming, Calvin runs up to Hobbes and explains the situation. Later when Rosalyn appears, Calvin and Hobbes hear that Rosalyn needs to study for a big science test. They decide to ruin her studying. After Calvin's parents leave, Calvin approaches Rosalyn, curious about what she's doing. After slyly talking her away from her science notes, he quickly grabs them, runs to the bathroom door with Hobbes, and locks the door while Rosalyn yells from he outside demanding her notes back. Once they "flushed" her notes (in which they only pretended to and flushed an empty toilet). Moments later when the wonder if Rosalyn has gone, Calvin opens the door only to find Rosalyn pounce upon him and throw him to bed at 7 o'clock which Hobbes notes that they went to bed 30 minutes later than usual. The ending shows Calvin's parents coming back home to find Rosalyn charge extra money for the job while Calvin's parents argue if there's another babysitter in town.