- The Noodle Incident (as in, the Noodle Incident) never gets explained, though whenever someone mentions it, Calvin becomes panicked and defensive. Watterson stated that he originally intended to explain it, but realized he couldn't make up anything that would be as funny as what the readers would invent trying to figure it out.
- On a related note, in a one-off strip, Hobbes mentions an event dubbed "the salamander incident", which Calvin claims temporary insanity in. Whether or not it relates to the later mentioned "Commander Coriander Salamander" is unknown.
- Calvin's favorite bedtime story, Hamster Huey and the Gooey Kablooie. Similarly to the Noodle Incident, Watterson is on record as saying that he will never define what the story is actually like, because inevitably it would be funnier in the reader's head. There's also the sequel, Commander Coriander Salamander and 'Er Singlehander Bellylander, which is mentioned in only a single strip and which Dad has an even lower opinion of. Funnily enough, there now is a children's book (of dubious quality) named after the first fictional book, by one "Mable Barr" (the in-universe writer was "Mable Syrup").
- The only hints revealed of what was in the book is that there is a dance called the "Happy Hamster Hop", and that reading it aloud requires "squeaky voices and gooshy sound effects".Mom: But you look so cute doing the Happy Hamster Hop.
Dad: I don't WANT to look cute!
- Once, Calvin's dad got irritated with the actual story and began to ad-lib; we didn't hear that story either, but Calvin and Hobbes are visibly terrified afterwards and Hobbes wondered at the end whether the townspeople ever found Hamster Huey's head.
- The only hints revealed of what was in the book is that there is a dance called the "Happy Hamster Hop", and that reading it aloud requires "squeaky voices and gooshy sound effects".
- In one strip, Calvin complains to Hobbes about how much trouble he got into that day in school, but when Hobbes asked what happened, Calvin says he doesn't even want to talk about it. When Hobbes asks if it had "anything to do with those sirens [he heard] around noon", Calvin repeats, louder this time, "I SAID I don't want to talk about it."
- In the strip that immediately preceded this one, Calvin is getting dressed for school, complaining about how it never changes, and then says, "Well, not today. Today, I go for the gusto." and puts on a cape and space helmet, which seems to suggest the obvious.
- Calvin tells Dad it's amazing how many things you can take apart with just an ordinary screwdriver. Dad says, "Such as?" Calvin realizes he's said too much and stammers that he doesn't really know and was just speaking hypothetically. Then he walks away, telling himself that he needs to stop introducing topics of conversation. How many things did Calvin take apart with a screwdriver, and what were they?
- In one strip, Calvin tells his dad that it's possible to buy live squid at the supermarket. His dad half-registers this... then realizes what's going on and screams, "CALVIN, WHAT ARE YOU DOING?"
- A similar strip had Calvin ask his mom if rotten eggs smell bad. His mom tells Calvin they indeed smell terrible, before the realization of someone like Calvin asking that kind of question sets in, at which point she tells him to "put 'em back".
- Another strip has Calvin's dad coming home from work, only to see Calvin with a sheepish grin holding up a sign that says "love the sinner, hate the sin". He immediately realizes Calvin's done something really bad while he was at work, but the strip never reveals what.
- Calvin's show and tell from this strip... if he even had a show and tell.Calvin: Today for "show and tell", I refuse to show you what I brought and I refuse to tell you anything about it! It's a mystery that will haunt you all your miserable lives! You'll never, ever know what I brought! You can beg and plead, but I'll never end your torment! I'll carry my secret to the grave! It's the show and tell that was never shown or told! Ha ha ha! Ah ha ha ha ha!
(Cut to Calvin walking to the principal's office)
Calvin: Everybody wants the same old thing.
- A very similar strip has Calvin interrupt a lesson to announce a "teaser" for his show and tell item tomorrow. There's no followup to this strip, so the reader has to come up with their own ideas of what it was.Calvin: Hey kids, on tomorrow's show and tell, I'll be bringing a big surprise! Will it shock or amaze you...or will it disgust and terrify you?? Find out tomorrow when I reveal my next show and tell horror! Don't miss it!
- In one strip, Calvin and his mom come back from a children's matinee movie. He had barely noticed there was a movie on, and she looks messy and extremely tired (and demands they purchase a video player when asked how it went by her husband). Obviously he found something else to do.
- In one strip, Calvin asks Hobbes a "hypothetical" question about whether he should tell Dad if he's done something bad. Involving his car. Which could perhaps be repaired if it could be found first...note Calvin: Hey Dad, remember our car?
Dad: Why sure... Wait a minute, what do you mean "remember"?
- Calvin once called his dad and asked him to pick up topsoil and grass seed on his way home from work. Dad, being busy, brushes it off with "OK, sure. Goodbye." We then see Calvin walking away from the phone covered in dirt and carrying a big shovel and pickaxe, and Calvin's dad looking very puzzled.
- Another strip has Calvin asks his dad, "Would you still love me if I did something bad?" He means something "really, really" bad. Dad yells, "CALVIN, WHAT DID YOU DO?!?"
- Calvin's parents are once shown discussing child rearing after "the contractor says it will cost $200 to fix". It's never mentioned what exactly Calvin broke.
- One strip shows that Calvin flooded the house. How he did this is never touched upon. As with the crashed car incident, there was a later Story Arc that showed just how a milder version of the same thing happened another time.
- A similar strip had Calvin and Hobbes sitting on the counter helplessly watching a waterfall from the overflowing kitchen sink flood the house. Why and how this happened is not mentioned.
- Another strip, he's worried about his dad finding out he broke his dad's binoculars. When Hobbes suggests that maybe Calvin could repair the binoculars, Calvin goes and gets the binoculars. He brings a box and tells him "don't sneeze" as he pours out a pile of very tiny pieces. While it was mentioned in the previous comic that he was tossing the binoculars in the air while running down the sidewalk, how it went from that to a pile of dust is not explained. This could be more about comedic exaggeration than implying an actual incident.
- The throwaway gag in this strip◊, we never find out what Calvin said about his dad by writing in the snow. Similarly in this strip, Calvin's dad doesn't even want to know what he planned to write when he said he wanted to write messages in gasoline and light them on fire at night so airline pilots can read them from overhead.
- Many strips involving C&H's infamous sled and wagon rides are left mostly to the readers' imaginations. For example, in one strip the sled apparently caught fire before they crashed it into a pond, while in another, the wagon somehow launched itself and them into the boughs of a tree so tall they could see for miles.
- A similar sort of strip has Calvin, having build a loop-the-loop out of snow, about to test his toboggan on it. Hobbes doesn't believe it'll work, but he'll gladly watch Calvin try anyway. We don't find out what happens in the end.
- The first strip of the story arc about Uncle Max (Calvin's dad's brother) had this exchange about why they haven't seen him in a while.Calvin: Why not? Was he in jail?
Mom: No! Good Heavens, Calvin!
Dad: Now now, with Max, that's actually not a bad guess.
- One Christmas strip has Calvin's furious mother throwing him out of the house for singing a novelty Christmas song too many times. We never find out what novelty Christmas song exactly it was.
- One story arc had Calvin's parents taking him to the zoo. While at the monkey house, Calvin notes that one of the monkeys is doing something gross in public and asks why he isn't allowed to do that. What the monkey is doing is never shown or described; Calvin's parents just try to redirect his attention to some birds.
- After a week-long camping trip suffused by rain from beginning to end, only for the sun to appear immediately after everything was packed up, the final panel implied that Calvin's dad let out a Cluster F-Bomb in frustration. We never learn what he said, or if it was a simply a case of Angrish similar to the father's reaction when he drops something heavy on his foot.Calvin: (eagerly) Do you know what any of Dad's words meant?
Hobbes: No, but I wrote some of them down so we can look 'em up when we get home.
- Several strips allude to Calvin having gone through several babysitters before settling on Rosalyn. We're not told any details, but apparently everyone's experiences with Calvin were so bad, nobody in town except Rosalyn will agree to babysit him anymore. Considering what we see Rosalyn put up with, their experiences must have been quite spectacular.Mom: You remember Amy? She just laughed when I called her.
- Calvin asks Mom where the extension cords are and she tells him. Then he asks about the blades for Dad's electric saw and she suspiciously asks why he wants to know. Calvin claims to be making an inventory list so the family will always know where to find things. Naturally, Mom doesn't believe him. We never find out what he was really planning to do with the electric saw.
- In the story arc where Calvin rips his pants during recess, Miss Wormwood forces him to solve a math problem at the board, not knowing that his underwear is showing. We're not shown what happens next, but apparently, "complete pandemonium" ensued on a scale so great that class was cancelled.Hobbes: That's why your home early?
Calvin: Three teachers and the principal couldn't restore order.
- In an early story arc, Miss Wormwood was sick and replaced by a substitute teacher. Calvin is immediately adverse to the substitute and apparently he did... something... that made her leave at noon.
- There's a minor Running Gag of Calvin capturing some sort of creepy-crawly critter which is not shown to the audience, only for it to somehow get loose... leaving the audience to wonder what horrible thing has been inadvertently set free.
- In one strip, Calvin walks up to his dad with something cupped in his hands and asks him to close his eyes and open his mouth for a big surprise. His dad, obviously not trusting Calvin, keeps his eyes just barely open, which upsets Calvin that his dad doesn't trust him. But then in the last panel...Calvin: Uh oh. Hang on, he got away.
- In another strip, Calvin brings some "little guy" in a paper bag to school for show and tell, but then when he looks inside the bag during the presentation, there's nothing inside.Calvin: Have you all had your shots?
- Yet another strip has Calvin asking his mom if he found anything... weird inside his pant pockets when she put them in the washing machine. When she tells him she didn't find anything, he gets worried.Calvin: Let's just say we need some big gloves and a heavy stick... fast.
Calvin's Mom: Do you mean you don't know where this thing is?!
- In a different strip, Calvin asks his mother if she felt anything funny when she put on her clothes today, like a sting or a bite. When she asks why exactly she would've felt anything "funny", Calvin hands her a can of bug spray and a flyswatter and then runs away. The last panel shows his mom hastily throwing off her clothes.Calvin's Dad: Women! Always changing their clothes!
Calvin's Mom: After I get that kid, you're next.
- A strip with a very similar joke has Calvin having Susie guessing what he has cupped in his hands. Susie, knowing exactly what Calvin is like, gets very close very quickly, but quits before giving a direct answer.Susie: Is it some creepy, gooey thing that no one in his right mind would ever, ever want to look at?
Calvin: Uh... I suppose that depends on your point of view...
Susie: Forget it. I'm not guessing.
Calvin: You might as well. You're nine-tenths there.
- In one strip, Calvin walks up to his dad with something cupped in his hands and asks him to close his eyes and open his mouth for a big surprise. His dad, obviously not trusting Calvin, keeps his eyes just barely open, which upsets Calvin that his dad doesn't trust him. But then in the last panel...
- In the opening of one Sunday strip, Calvin's dad is relaxing in the yard when he sees an absolutely filthy Calvin walk by. He asks Calvin how in the world he got so dirty, but all he gets is a totally unbelievable story where he escaped a Cannibal Tribe. Realizing that he's not going to get a real answer, Dad doesn't bother listening to the rest, leaving it up in the air why Calvin is so dirty (aside from the most obvious explanation that he just jumped into a mud puddle).
- In one strip, Calvin doesn't want Hobbes to join him in the pool because he'll get hair in the water. Hobbes then proceeds to intentionally shake his fur off into the pool to get Calvin to leave. Only when Hobbes gets into the pool does Calvin reveal he put something much worse in the water.Calvin: You think you've won, huh? Well, I'm not even going to tell you what I did.
- A large number of strips involve Calvin doing, about to do, or having done something that is going to get him into big trouble, but it leaves it up to the readers' imagination just how and when he ends up getting inevitably punished.Hobbes: You don't think your dad will get mad about us digging up the driveway?
Calvin: Oh, you know dad. He'll get mad no matter where we dig.
- Calvin's comically long Christmas wish lists. We only get a few glimpses of what's in them (mostly heavy-duty weaponry that no sane six-year old would ever wish for), but not nearly enough to account for the fact the lists require boxes and several dollars worth of postage to mail them.
- In one strip, Calvin walks up to his mom and, totally unprompted, tells her that he was sucked into another dimension, and could only watch helplessly as he was replaced by an Evil Doppelgänger. At this point, Calvin's mom realizes what's going on and demands to know what Calvin did this time. The audience is left to wonder, however.
- One story arc has Calvin's mom go to his school for a parent-teacher meeting. We're not told much about what happened, only that the meeting quickly "went downhill", and Calvin's mom almost immediately slumps down on the couch exhausted recounting the meeting to her husband. This story arc is also the first mention in the story of the infamous and aforementioned "Noodle Incident", itself another example of this trope, but apparently the meeting did not mention the event.
- In a one-off strip, Calvin tells his dad that he wants everyone in the household to talk to each other only using "ten-second sound bites" from now on. Calvin's dad then proceeded to tell Calvin some "sound bites", which the reader isn't privy to, that causes Calvin to immediately reverse his choice.Calvin: (covering his ears) So much for that policy.
- One strip has Calvin complaining to his teacher that his "F" on his assignment must mean she does a bad job of teaching him. Her reply is depicted in form of an alien monster's incomprehensible snarling and growling, leaving it the reader's imagination what she said.
Nothing Is Funnier / Calvin and Hobbes