Secondary characters in Calvin and Hobbes
Watterson has never given Calvin's parents names "because as far as the strip is concerned, they are important only as Calvin's mom and dad."  However, Watterson sometimes uses them to explore situations adults can relate to, such as the desire to enjoy leisure time as opposed to the need to work, or bad customer service and frustrations when grocery shopping. Also, occasionally Watterson takes the time to flesh out the two parental characters. One example is a storyline in which the family returns from a wedding to find their house has been broken into and ransacked. For several strips, Calvin and Hobbes fade into the background as Mom and Dad reflect on the impact of the event.
Early on in the strip, Watterson says, they were criticized by readers for being overly sarcastic and insufficiently patient, especially Calvin's father, who has several times reminded his wife that he at first, wanted a dog instead of a son. Calvin's mother has been hinted to have possibly wanted a girl, and at one point, Calvin's antics frustrated them so much that they acted like they were sorry to have had him. Later strips would depict Calvin's parents being more demonstrative of their love for their son, while still being driven crazy by his trouble; for example, When Calvin wanders off at the zoo, his father says, as he goes to look for him, "Being a parent means wanting to hug and strangle your kid at the same time." In another strip, Calvin wakes his mother up at 12:00 AM to ask if love is nothing but "a biochemical reaction to make sure our genes get passed on". Irritated because he woke her up in the middle of the night, she responds with: "Whatever it is, it's what's keeping me from strangling you right now".
Calvin's parents drive a purple or maroon subcompact hatchback similar to an early 1980s Honda Civic or Volkswagen Golf. This may be because Bill Watterson drove a Civic himself. The car is the setting of family trips, and is occasionally the victim of Calvin's mischief, such as the long story where he accidentally pushes the car into a ditch. The car is usually drawn as bouncing along the road as it drives, to give it the illusion of motion. There may also be another car, as in one strip, when Calvin's parents went out to dinner (Rosalyn appeared), Hobbes suggested they learn to drive "using the other car". But in another strip, Calvin attempted to play hooky from school, and after his mother captured him, she said his father would be late for work because she had to drive Calvin to school (which could not happen if there was a second car). It is possible that the car was broken down, and that the car wasn't mentioned.
Calvin's father is a patent attorney, portrayed to the reader as an upstanding middle-class father despite how his son may see him. An outdoorsman, he enjoys bike rides and camping trips, sometimes in extreme weather and insists that these activities, like Calvin's chores, "build character". Though his age is never specified, when Calvin offers him a bowl of chocolate cereal, he replies "No thanks, I'm trying to reach middle age."
When Calvin asks him questions, he often makes up sarcastically outlandish answers and presents them as facts. For example, Calvin's father once said that the wind is caused by trees sneezing (though when asked if this was true, he responded, "No, but the truth is more complicated."), and that light bulbs and vacuum cleaners work by magic. Calvin always appears to believe the answers, despite his mother's reactions, as Calvin said, "I take it there's no qualifying exam to be a dad". It is interesting to note that to be a patent attorney traditionally requires a natural science or engineering bachelor's degree preceding the usual Juris Doctor needed to practice any other branch of law — something Watterson would know, as his own father was a patent attorney — and therefore, Calvin's father presumably does know the real answers to his son's questions but whether or not this is true would depend on what inventions Calvin's father represents. There are occurrences when the reader should assume that "Dad" really does know the answers and decides to mislead Calvin purposefully. For example, when Calvin asked his father where babies come from, he was told that most people assembled babies from a kit that could be purchased at Sears. Calvin's father told his son that he was a "Blue Light Special at Kmart, almost as good and a lot cheaper."
This playful streak allows him to find occasional moments of solace with Calvin, and it is implied that Calvin's father may have been like Calvin in his youth. Calvin has described his traditionalist father as "the most boring Dad in the world" (after he refuses to throw an entire can of lighter fluid into a campfire). Though apparently a believer in traditional values, such as insisting the family sit down for dinner at table without distractions, Calvin's father may also have been a party animal in college: in one strip, Calvin is looking through his father's college yearbook and finds a picture of him standing next to a keg, wearing a "Party Naked" T-shirt (upon which his father hurriedly grabs the yearbook away); in another strip, Calvin's father defined "the ol’ college try" as, "when you gather your friends, grab some cheap beer, order a pizza, and forget about tomorrow."
Calvin seems not to understand why his father occupies this position, and assumes that it is an elected position. He frequently presents his father with his polls and lectures him about his public image. There were several strips with Calvin saying that his father's popularity is slipping; in one strip, Calvin fantasized what the papers will look like when his father is defeated in the next election. His father pays little attention to Calvin's campaigning — especially since the polls invariably focus on the 6-year-old-male and stuffed-tiger demographics. Calvin's father frequently makes witty comebacks to Calvin's "polls", such as "Instances of true leadership. History will vindicate me."
Watterson occasionally used Calvin's father to comment on various aspects of adulthood. The latter seems frustrated with the constant rat race and struggle to get ahead, and is ambivalent about America's consumer culture, once commenting that pitching the day's allotment of junk mail make him a "terrorist" for not "buying distractions from a simple life". Calvin's father seems happiest when he is riding his bike or sitting in the backyard watching the sunset, enjoying peace and quiet, and is sometimes seen spending time with Calvin. Ironically, he sometimes goes to the office to escape Calvin when the latter is up to trouble (and on some occasions his wife as well). Not to be evaded, Calvin tracks down his father on the phone and frequently brags about how Calvin and his mother get to relax during summer whereas he has to work at the office.
Calvin's father is particularly shaken when the house is robbed. He reflects to Calvin's mother that adulthood is "ad-libbed".
The character is based on Watterson's own father, who was also a patent attorney, and often told his family that unpleasant things "built character". As can be gleaned from a photograph and self-caricatures of Watterson, Calvin's father bears a striking resemblance to the cartoonist himself, who sports a mustache. Watterson has said that he identifies more with this character than with Calvin.
Calvin's father seems to be reluctant to accept modern technology, and has shown great distaste for television on occasion. Calvin has mentioned that his dad prefers communication by mail, and Hobbes has remarked, "Of course, your dad thinks transportation should've stopped with the bicycle." Calvin pointed out that his dad has neglected to buy a VCR, which at one point led to his dad saying "How cruelly we mistreat you, Calvin." and giving Calvin a copy of Oliver Twist. In one strip Calvin tells his father that he would do better on his school book reports if they had a computer, to which his father replies "You'd still need to read the book and tell the computer what to say." After the family does buy a computer, Calvin wonders why their computer doesn't have an Internet connection, Calvin's dad responded "It's bad enough that we have a telephone." Calvin's mom has pointed this out too: in one strip, she and Calvin return home from a kids' matinée, Calvin's father asks Calvin "How was the kiddy matinée movie?"—Calvin vaguely remembers that he saw a movie and stated it was OK; when Calvin's mother enters, visibly worn out from whatever antics took place, she grabs the front of his shirt and angrily tells him "We ... are ... buying ... a video player."
There are serious father-son moments between Calvin and his Dad. After a baby raccoon the family rescued dies, Calvin breaks down and cries while his father tries to comfort his grief and explain the facts of death. The most sentimental strip involving Calvin and his father is a nonverbal Sunday comic in which Calvin wants his father to play outside in the snow with him. Calvin's father at first reluctantly declines in order to do paperwork. After a disappointed Calvin leaves, his father changes his mind and joins Calvin outside , where the two of them build a snowman. The last panel shows Calvin's father working late finishing his paperwork, while Calvin's mother holds their son up to his father's head to kiss him goodnight.
Calvin's mother is a stay-at-home mom who is frequently exasperated by Calvin's antics. Before Calvin's birth, she worked a stressful job filled with aggravation, which Calvin's father claims is the reason she was better prepared to stay at home and raise Calvin. Whether or not he was jesting is debatable. On the rare occasions when she is not reacting to Calvin's misbehavior, she seems to enjoy quiet activities, such as gardening and reading. She is frequently the one forced to curb Calvin's destructive tendencies; in one Sunday strip, she allows Calvin to smoke a cigarette in order to teach him how unpleasant smoking can be. She also usually seems sympathetic towards her son's relationship with Hobbes, and a few times has found herself speaking to Hobbes as well, though this embarrasses her. She has even called out to Hobbes once the same way Calvin did when she was looking for him, perhaps implying that, like her husband, Calvin's mother also has her own moments of playful imagination, despite generally being a straight-laced adult.
Watterson has said he regrets the fact that the strip mostly shows her impatient side. She is sometimes seen kicking Calvin out the front door whenever he dramatically annoys her, but he also tried to show other aspects of her personality by what she is doing when Calvin invades. She keeps a clean house, as she is occasionally found refinishing furniture or painting the walls. She also seems to have an active social life, writing letters and leaving phone messages for friends, even inviting friends over for tea on occasion. Needless to say, Calvin tends to interfere with these things.
Although Calvin's behavior drives his mother crazy (Calvin once quipped "another day, another gray hair for Mom!"), she still loves him very much. When Calvin was lost on a trip to the zoo, she became sick with worry, and was thrilled when his dad brought him back. When she becomes ill in another story, Calvin tries to tend to her like she does to him when he's sick. His mom says "No thanks" and Calvin replies with "It's hard to be a mom for a mom". Then she gets up and hugs Calvin, Saying "You do fine, sweetie". Calvin freaks out and tries to get away, fearing that his Mom might be contagious. In one strip, she is shown chasing Calvin shortly before bedtime, tickling him whenever she catches him; in the end, Calvin explains to his father, "Her plan backfired, Dad. I'm all wound up, and Mom needs to be put to bed."
She has also stepped in when his father goes too far with his own private jokes, going so far as to say "I know somebody who's going to get a lot of coal in his stocking, buster" after his dad tells him that the family will keep the undecorated Christmas tree in the garage and that Calvin might not get gifts. She frequently scolds her husband for his sarcasm in dealing with their son. She is also shown to be on Calvin's side when they go for their usual camping trips, complaining just as much as her son about these outings; says she, "a whole week without a newspaper or a decent cup of real coffee!" She can sometimes calm Calvin down when he is in a bad mood, offering peanut-butter crackers, comic books and other treats to cheer him up. Though she is almost always shown criticizing Calvin's behavior, it is revealed that she may have been problematic when she was a child as well. In one strip, she tells Calvin, "Someday I hope you have a kid that puts you through what I've gone through", to which Calvin replies, "Yeah, Grandma says that's what she used to tell you".
She, like Calvin's father, may have been a party animal in her college days. In one strip Calvin looks through a college yearbook and pictures and asks his father who the "bimbo" in the picture is, to which he responds "that ‘bimbo’ is your mother!". This also implies that the two were fellow students and/or juvenile "crushes".
Calvin claims to dislike his mother's cooking, to the extent that she must trick him into eating it, often by telling him that it is something disgusting such as "monkey heads,"boiled guano", "spider pie", or "maggots", enticing him but disgusting her husband. Calvin's liking of the food depends on his mood and the activity that he'd rather be doing instead of eating, such as watching TV, though his main concern regards the appearance of the food itself. He would claim to love a dish one week, only to hate it the next week. In one strip, Calvin even claimed his mother used shrunken heads, an octopus, weed killer and white paint in one of the meals. In another strip, Calvin even gets the idea that his mother regurgitated the meal, having just seen a nature documentary where it explained that mother birds regurgitate their meal for their brood. Another example has Calvin fantasizing that his mother has doctored his meal, making it eat Calvin and spit out his skull, leading his parents to perform a celebratory dance.
Although she loves him very much, Calvin's mother has sometimes commented that she wanted a daughter instead of a son. In one instance, she has even blamed her husband for giving her the chromosome that determined Calvin's gender. Calvin himself has even said that she thinks of this; after she turned down Calvin's offer of helping around the house with unnecessary carpentry, he stated: "Mom wanted a girl. I just know it."
Calvin's Uncle Max appeared in a series of strips in 1988, visiting the family. Uncle Max is Calvin's father's "big brother", though he is established as single and childless. Like typical brothers, they often joke with each other. When Calvin (who first suspected he was a con man trying to swindle them) guesses that Max was in jail (to explain why he hasn't met Max), his mother is outraged, while his father seems to agree with Calvin, saying "with Max, that's not a bad guess". He seems to be more in tune to Calvin's interests than his parents. He seems to have a good relationship with children and does not take Calvin's jokes literally, which is the main reason why Calvin and Hobbes like him. On one occasion Max enters his room to find Calvin has dumped out his suitcase, believing Max brought him a present. Max, annoyed, asks, "Did your Mommy and Daddy raise you like this, or did they just untie you for this visit?"
Watterson has said Uncle Max was meant to be included in further strips, such as where the family would go to Max's home to pay him a visit; he never appeared again because Bill felt that it was strange for Max to be unable to refer to the parents with proper names, as Watterson never gave them any, and that the character never provided the new material for Calvin that he had hoped for.
Calvin has a maternal grandmother and grandfather. A grandfather who smokes is mentioned, but it is unclear whether he is maternal or paternal. None appear in the strip, and are rarely mentioned.
A grandfather is mentioned during a scene on May 25, 1986, where Calvin smokes a cigarette (and winds up in a coughing fit). Before he does this, Calvin's Mom says, "I think your grandfather left some in the back." A reference was made to Calvin's maternal grandfather when Calvin is describing him, his comments echoing Bill Watterson's complaint that comic strips are too small and now look like Xeroxed talking heads. Hobbes then tells Calvin that his grandfather takes comic strips seriously; Calvin says as a result, his mother is looking into nursing homes for him, implying that this grandfather is maternal.
Calvin's maternal grandmother is mentioned after Calvin misbehaved in the doctor's office, when his mother tells Calvin, "Someday I hope you have a kid who puts you through what I have gone through.", to which Calvin replies, "Yeah, Grandma says that's what she used to tell you." She is also mentioned when Calvin's mom is typing on a typewriter. Mom: "Who wrote 'Help I'm a bug' on my letter to Grandma?" In another strip, Calvin is writing a thank-you note to Grandma for sending him a box of crayons as a gift. Hobbes comments on the quickness of the note, and Calvin says "Yeah, I always write her a thank-you note right away...ever since she sent me that empty box with the sarcastic note saying she was just checking to see if the postal service was still working." Also, in another strip, Calvin makes "funny" expressions on his school pictures and comments that he can't wait for his mom to send his picture to Grandma.
Susie Derkins is a classmate of Calvin who lives in his neighborhood. She is the only recurring character in the comic strip to have both a forename and a surname revealed (other characters are mentioned briefly). She is also the only character who aged in the strip. Named after Watterson's in-laws' family beagle, she first appeared early in the strip as a new student in Calvin's class, but in later strips speaks as a longtime neighbor. In contrast to Calvin, she is polite and diligent in her studies, and her imagination usually seems mild-mannered and civilized, consisting of games such as playing "house" or having tea parties with her stuffed animals. Her parents have spoken in the strip several times, but it is never confirmed that they appear.
Susie is frequently the victim of Calvin's derision and plots, and is also often willing to retaliate when provoked. Most commonly, Susie will be the target of Calvin's water balloons or snowballs. Calvin often goes to great lengths to disgust or annoy Susie, as when founding his and Hobbes' club 'G.R.O.S.S.' (Get Rid Of Slimy GirlS) purposely to oppose her. Susie is Calvin's equal (and often superior) in cunning, often turning his plans into ignominious defeats. Susie has a short temper, which is shown in several strips in which she beats up Calvin for simply throwing a single snowball or water balloon at her. She also possesses strength, as in one strip she picked up Calvin and carried him over to a giant snowball to dunk him in after he threw a snowball at her, and is apparently on the school's lacrosse team, as shown in one strip where Calvin throws a pine cone at her, only to have her return it at higher speed. The only nonviolent interactions between the two, occur Calvin attends Susie's birthday-party, and again when Calvin questions whether or not to join a baseball team, wherefore the two mildly discuss Calvin's dilemma while sharing a seesaw. Hobbes has a crush on Susie and can sometimes persuade Calvin to play with her. The two sometimes speak at their bus stop, where both become exasperated by their conversation; and at the lunch table, where Calvin recites disgusting descriptions of what his lunch contains. Elsewhere, Susie becomes frightened that Calvin's irresponsibility shall threaten her post-secondary education, or argues in academia's favor against him.
Watterson has said he suspects that Calvin and Susie may have a mild crush on each other, and that "this encourages Calvin to annoy her". This love/hate relationship is most obvious in a Valentine's Day strip in which Susie seems to appreciate "a hate mail valentine and a bunch of dead flowers", and Calvin rejoices inwardly when she retaliates. In another strip, Calvin calls Susie for help with homework, and she teases him that he missed "the melodious sound of my voice". During one series of strips Calvin modifies his "duplicator" to copy only his good side; this well-dressed, polite, and very-intelligent version of Calvin soon becomes besotted with Susie, and is mystified by her hostile reaction.
Mr. Bun is Susie's stuffed rabbit, which frequents her tea parties as a guest. Unlike Hobbes, Mr. Bun is never shown as a living character, and Hobbes once described Mr. Bun as "comatose". This is used for comedic effect occasionally, as when Susie, playing "House" with Calvin, attempts to use Mr. Bun as their baby child, only to have Calvin refuse to recognize him as a human infant—with the entire strip, including the rabbit, drawn in a realistic style à la Rex Morgan, M.D..
Miss Wormwood is Calvin's schoolteacher, named after the junior devil in C. S. Lewis' The Screwtape Letters. She usually wears polka-dotted dresses, and serves as a foil to Calvin's mischief. Despite a large progression of time in the Calvin and Hobbes Universe (10 years), mainly exhibited by the changing seasons, every character seems to remain exactly the same age, with the exception of Susie. As a result, Calvin and Susie return to Miss Wormwood's first-grade class every fall. (Watterson has explained that comic-strip characters typically do not age.)
Miss Wormwood is rarely sympathetic to the trouble Calvin has in school, and comes across as a rather strict, sour character. She often calls on Calvin to answer questions, to catch him off guard, to which Calvin either replies with an excuse ("Hard to say, Ma'am. I think my cerebellum just fused."), or takes solace in the world of Spaceman Spiff or another alter ego. She is quick to send Calvin to the principal's office at the first sign of trouble. Calvin apparently takes joy in being the reason why Miss Wormwood mixes different stress-related medications, "drinks Maalox straight from the bottle", and is anxious for retirement (one strip has her chanting in her head, "Five years until retirement, five years until retirement, five years until retirement..."). In one particular strip, Calvin implies that she smokes ("They say she's up to two packs a day, unfiltered."). Regarding the difficulties of reining in rambunctious students, she once commented that "it's not enough that we have to be disciplinarians. Now we need to be psychologists". Given that the strip gives much attention to playful imagination, she may represent the "real world" and its frustrations in trying to permit or control extreme creativity. In one strip, Miss Wormwood is shown handing a marked test to Calvin, angrily declaring "Calvin, your test was an absolute disgrace! It's obvious you haven't read any of the material! Our first president was not Chef Boyardee, and you ought to be ashamed to have turned in such preposterous answers!", to which Calvin remarks, "I just don't test well". In another strip, after stating that he could not identify Plymouth Rock, lest it "compromise our agents in the field," Calvin cheerfully remarks, "I understand my tests are popular reading in the teacher's lounge". In his Spaceman Spiff persona, Calvin usually imagines Miss Wormwood as a slimy, often dictatorial alien.
Moe is the stereotypical bully character, and one of the primary villains, along with Rosalyn and the Monsters under the Bed. His (frequently monosyllabic) dialogue is shown in crude, lower-case letters (probably the most intellectual words Moe has ever used are "asphalt" "spatula", and "skin grafts"). Watterson describes Moe as "every jerk I've ever met " and reflects his memory of "school being full of idiots like Moe." . Moe is the only minor character in the strip who hurts Calvin without being provoked, and is also the only significant character never portrayed with sympathy. Moe steals Calvin's toy truck by threatening to punch him, and when Calvin demands it be returned, taunts Calvin to a "fight" over it. Calvin is disgusted by Moe's lack of conscience and angrily tells him off "You're the one who has to live with yourself! I can't make you do what's right! You can HAVE the stupid truck!" To which Moe coldly responds "Ok, thanks! Heh. Heh."
Stephan Pastis of the 2000s comic Pearls Before Swine has cited Watterson and Calvin and Hobbes as among his many influences; in particular, the Zeeba Zeeba Eata fraternity of crocodiles is identified with Moe, even speaking in the same typeface.
Rosalyn is a high school senior and the only babysitter able to tolerate Calvin's antics. Calvin is often terrified of her; but in the final Rosalyn story, their opposition is averted by a game of Calvinball, which Rosalyn wins (this makes Rosalyn the only character in the strip to have a conclusive story arc). In nearly all the "Rosalyn stories", Rosalyn is shown demanding advance payment and raises in wage from Calvin's parents, supposedly to pay for college or for the hard work necessary to control Calvin. (For the same reason, she briefly appears as Calvin's swimming instructor.) In at least four stories, Rosalyn telephones her boyfriend, Charlie, to cancel prearranged meetings which she cannot fulfill. (Charlie remains an unseen character.) Calvin sometimes urges Charlie to stop courting Rosalyn, on grounds that Rosalyn is sadistic and/or insane. Rosalyn is one of the only two major characters with no role in a Spaceman Spiff strip; the other being Hobbes.
- Living Food: Calvin often imagines that an oatmeal-like food comes to life, sometimes attacking him. Bill Watterson has said that his inspiration for this came from a cartoon drawn by himself in childhood, which featured living oatmeal.
- Extraterrestrial Life Forms: Calvin encounters many extraterrestrial life-forms in the course of the strip, usually during adventures as his alter-ego, Spaceman Spiff. Most of these aliens are non-humanoid, bizarre monsters, but represent Calvin's imaginative perception of Susie, his parents, and teachers. Initially, many of the aliens spoke in garbled, somewhat onomatopoetic language, with lines like "Ugga muk bluh Spiff." Later, some aliens' speech balloons contained geometric symbols with unclear phonetic values, or had a blocky, semi-computer-like font. In the strip's final year, Watterson drew two stories involving recurring alien characters, Galaxoid and Nebular, to whom Calvin 'sold' the Earth for 50 alien leaves to use for his science project, which he failed when his teacher rejected the leaves' origin. The donors returned in the final two weeks of strips, angry at Calvin for failing to reveal the changing seasons; but were placated when Hobbes clad them in Christmas stockings.
- Doctor: Calvin occasionally visits his pediatrician, who appears to be a mild-mannered physician with a friendly demeanor. Calvin, however, sees him as a vicious, sadistic interrogator, sometimes imagining him as an alien or overreacting to playful diagnoses. The doctor made his final appearance when he diagnosed Calvin with chicken pox.
- Principal Spittle: Calvin's school principal usually makes his appearance when Calvin has upset Miss Wormwood; typically, he is seen looking over his desk as Calvin tries to explain his latest mishap, with an apathetic or infuriated expression in his face. He is seldom shown speaking except in his first appearance. He is depicted thinking to himself that he hates his job.
- Classmates: The reader sees various classmates of Calvin, but other than Susie and Moe they are almost anonymous, and perceive Calvin as the misbehaving minority who makes things difficult for the conforming majority. Some appearances are Tommy Chesnutt (allegedly eaten by Hobbes), Russy White, Filthy Rich, Blake, Ronald, Jessica, Flow, Claire, Clarance and Candace. There are a total of thirty students in the class.
- Burglars: In one story, Calvin's family leaves Hobbes at home to go to a wedding, and their house is broken into, with the burglars taking the TV and some jewelry, but ignoring Hobbes.
- Mr. Lockjaw: Mr. Lockjaw is the gym teacher and coach of the baseball team at Calvin's school. He is a squat, burly man with little patience. When Calvin leaves the baseball team, Lockjaw calls him a "quitter", and this emotional trauma leads to the reader's first encounter with Calvinball.
- Scouts: Early in the strip, Watterson shows Calvin participating with other children in Cub Scout activities in the woods. Watterson thought at the time that scouting might offer some potential for interesting adventures, but eventually abandoned the idea, considering it uncharacteristic of Calvin to join an organization, and viewing it as a distraction. Later Hobbes uses a Cub Scout manual to get Calvin untied from a chair.
- Charlie: Also called Chuck or Chaz by Calvin, Charlie is Rosalyn's boyfriend, who telephones her during her assignments to Calvin; these are sometimes interrupted by Calvin himself, who attempts to portray Rosalyn as a "sadistic kid-hater".
- Susie's mom: She is shown from the waist down in a foiled attempt to pester Susie, and is also seen having a brief dialogue during Susie's first experience with Calvin's alter-ego, Stupendous Man.
- Substitute teachers: Occasionally, Calvin's class will have a substitute teacher, whereof only two are named. In one set of strips, a woman is substituting; she looks through some notes Calvin's teacher left and inquires which child Calvin is. Later, Hobbes asks Calvin what he thought of her, Calvin replies he is unsure as "she went home after noon."
- Mabel Syrup: The author of Hamster Huey and the Gooey Kablooie and Commander Coriander Salamander and 'er Singlehander Bellylander: two books preferred by Calvin.
- Monsters: the primary villains of the comic strip, along with Moe and Rosalyn: a set of bizarre-looking photophobic characters, who live under Calvin's bed and periodically plan to eat Calvin, but are outwitted by him on each occasion. One of them was named Maurice, and another one is named Winslow.
- Calvin's Bicycle: A supporting villain, it will frequently chase (and even sometimes run over) Calvin, destroying household items or injuring Calvin himself.
- The Martian: In one story, when Calvin and Hobbes visit Mars to escape environmental pollution, they become terrified when they meet a Martian. The creature is small, with several tentacles, with a large mouth, two eyes on eye-stalks, and covered in purple polka-dots with a green body. During the encounter, both parties are frightened on sight; later, Calvin and Hobbes speculate that pollution has given Earthly organisms a bad reputation, and return to Earth.
- Bill Watterson. "Cast of Characters". The Complete Calvin and Hobbes (press release). Andrew McMeel. Retrieved 2006-03-19.
- Calvin and Hobbes Comic Strip, December 20, 1987 on GoComics.com
- Calvin and Hobbes Comic Strip, November 10, 1987 on GoComics.com
- Calvin and Hobbes Comic Strip, December 12, 1987 on GoComics.com
- Calvin and Hobbes Comic Strip, May 25, 1986 on GoComics.com
- Calvin and Hobbes Comic Strip, November 09, 1987 on GoComics.com
- Calvin and Hobbes Comic Strip, December 29, 1985 on GoComics.com
- Calvin and Hobbes Tenth Anniversary Book, by Bill Watterson.
ISBN 0-8362-0438-7 (paperback)
ISBN 0-8362-0440-9 (hardback)
- Calvin and Hobbes Comic Strip, November 11, 1987 on GoComics.com
- Calvin and Hobbes Tenth Anniversary Book, by Bill Watterson.
ISBN 0-8362-0438-7 (paperback)
ISBN 0-8362-0440-9 (hardback)