Secondary Characters in Calvin and Hobbes - Rosalyn

Rosalyn is a high school senior and Calvin's official babysitter whenever Calvin's parents need a night out. She is the only babysitter able to tolerate Calvin's antics, a fact which she uses to demand raises and payment in advance from Calvin's desperate parents, starting from a meager eight dollars a night in her earlier appearances. She is also, according to Watterson, the only person Calvin truly fears—certainly she is his equal in cunning, and doesn't hesitate to play as dirty as he does. Originally created as a nameless, one-shot character with no plans to appear again, Watterson decided he wanted to retain her unique ability to intimidate Calvin, which ultimately led to many more appearances.

Rosalyn's idea of effective babysitting is a 6:30 bedtime for Calvin, and she has little patience for his attempts to rebel against her. Calvin will often freak out whenever he hears that Rosalyn is going to be babysitting him, in one instance screaming in protest non-stop for an entire strip (prompting his Mom to say in the last panel, "For goodness' sake, Calvin! Take a breath before you pass out on the floor!"). In one strip, she orders Calvin to go in the house and to his room, only to receive the reply "Jawohl, mein Führer!" and the Hitler salute. In the final Rosalyn story, however, the traditional war is averted by a game of Calvinball, in which Rosalyn proves to be a formidable player, and once again trumps Calvin with a clever move in the last panel. On returning home, Calvin's parents refuse to believe that she could play a game with him, much less convince Calvin to willingly go to bed, and assume she is making a joke. Occasionally, Calvin manages to gain the upper hand (or at least until his parents arrive) by tricking Rosalyn into precipitous situations, such as locking her out of the house so he and Hobbes can watch TV and eat cookies, or taking Rosalyn's science notes, which she needs to study for a test the next day, and locking himself and Hobbes in the bathroom and threatening to flush them down the toilet if she didn't give into his demands.

In nearly all the "Rosalyn stories", Rosalyn is shown demanding advance payment and raises in wage from Calvin's parents, supposedly because she needs the extra money to pay for college or for the hard work she puts into to control Calvin. (For exactly the same reason, she briefly appears as Calvin's swimming instructor.) They are reluctant to pay such exorbitant rates, but even more unwilling to have Calvin ruin their outings, as the overall reason they occasionally go out is to get a break from Calvin's antics. Therefore, they always gave Rosalyn her raise. When Calvin's dad protested one time on Rosalyn's constant demands for raises and advances, Calvin's mom said in a mad whisper, "Just pay what it takes to get us out of here!" Once after paying such an exorbitant rate (a moth is seen flying out of his empty wallet), Calvin's dad asks his mom if she's sure there isn't any other person willing to babysit Calvin, to which she responds, "Maybe you'd like to spend a week on the phone?"

In at least four stories, Rosalyn telephones her boyfriend, Charlie, to cancel prearranged meetings which she cannot fulfill. (Charlie remains as an unseen character.) Calvin sometimes breaks in and urges Charlie to stop courting Rosalyn, asserting that Rosalyn is sadistic and/or insane.

Her character was created for a Sunday strip for May 18, 1986 as an unnamed character. Because Watterson liked the character and her attitude toward Calvin, Watterson continued to bring her back. Because Sunday strips have to be done so far in advance, Rosalyn's first daily strip appearance took place three days earlier on May 15, 1986 (probably an accident). This means that the decision to continue using Rosalyn was made soon afterward. However, the storyline ended on May 17, 1986, the day before her only Sunday strip appearance.

Not only is Rosalyn Calvin's baby-sitter, she is also his swimming teacher. Calvin's mom took him for swimming lessons in one early story. While he's waiting for the lessons to start, he's worrying about how terrible the class will be. He says, "The only thing that could make this class worse would be if it were..." he turns and sees Rosalyn, "taught by my sadistic baby-sitter!" Calvin does not try to play any tricks on her, but he does fuss throughout the whole lesson, including complaining about the "dead-man's float" causing Rosalyn to remark, "What I put up with to pay for college." After the lesson is over, Calvin's mom tells him he is going to start taking piano lessons. However, Calvin is never shown taking Piano lessons, meaning she was either joking, or it was just never put into any strips.

Rosalyn is one of the only two major characters that never had any role in a Spaceman Spiff strip, the other being, interestingly, Hobbes (although Hobbes appeared at the end of one, it was in the real world, and not Calvin's imagination).