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 . 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 ). 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.
Get Rid Of Slimy Girls is Calvin's anti-girl club. The club's goal is to annoy and bother girls, and Calvin's main target is Susie Derkins. The club has only two members, Calvin and Hobbes. Calvin is "supreme dictator-for-life" and Hobbes is the "first tiger". They two usually make plans like throwing water balloons or snowballs at Susie. Often these plans have a bad ending. However, every time G.R.O.S.S finishes a mission or meeting, they always get awards such as medals, honors, and promotions. Of course, the word "gross" also means disgusting.
Although time does change in the Calvin and Hobbes universe, which is mostly seen in the changing of the season, Calvin (and Susie) returns to Ms. Wormwood's first-grade class every .
Hobbes shared his final appearance with Calvin in the final strip published on the 31st of December 1995. For the most part, Calvin and Hobbes converse and play together, revealing what is ultimately a deep friendship. They also frequently argue or even fight with each other, though their disagreements are generally short-lived.