Bill Watterson wants the reader to make up his or her own perspective of what ridiculous thing could have happened because of Calvin, mentioned in the Tenth Anniversary Book. Throughout the comic, the most that we learn is that it was presumably done by Calvin (though he maintains that he had been framed) and has caused him to worry about possibly not getting any presents from Santa Claus. Whenever a character, usually Hobbes, mentions it to Calvin, he immediately gets very defensive about it (He claims that no one can prove he did it). It appears to have happened at school due to Calvin yelling out loud, "She told you about the noodles, didn't she?!" when his mom came home from a parent conference. When Hobbes commented on the Incident, Calvin claimed that it was rather an accident.
- In one comic, Calvin complains about the downsides of his life and then states that today will be different because he will "go for the gusto." In the following strip Calvin tells Hobbes he got in big trouble at school. Hobbes asks Calvin what he did, and Calvin replies, "I don't want to talk about it." Hobbes then asks if it had anything to do with "all those sirens about noon" and Calvin says, "I said I don't want to talk about it", implying that it was a dangerous incident (because his reluctance to talk about it implies that it did involve the sirens) and that Calvin may be embarrassed about the incident. It is unknown whether or not these two strips were meant to be story arcs and it is also unknown whether or not one or both of them has anything to do with the Noodle Incident.
- In another comic, Calvin brought noodles to school for his report on the brain saying that it looked like a brain. Many believe this to be the Noodle Incident.
- It may have involved worms and something belonging to Calvin's father. In a strip where Calvin was reminiscing on not getting punished very severely over backing his parents' car into a ditch, Hobbes remarked "But, try keeping live worms in your dad's..."; at which point Calvin interrupted him and dismissed the issue very defensively, the same way he did when questioned about the Noodle Incident. Moreover, putting worms in spaghetti or another dish containing noodles is a common prank in the US and other countries.
- In one strip, Hobbes mentions "The Salamander Incident." However, it is unknown if the Salamander Incident was related to the Noodle Incident, or perhaps another name for it. If the latter is true, then the Noodle Incident may have also involved salamanders.
- In another strip, Calvin expresses disgust at the school cafeteria's manicotti. He then dumps the pasta down his shirt in secrecy, and a second later, exclaims to Susie, that his "intestines are bursting through his stomach wall", whilst opening his shirt, causing the manicotti to spill out, amplifying the effect. This causes Susie to flee in disgust. Calvin then suggests that if he could get some more to replicate the incident during math class, it might get him out of class early. Some believe that this is the noodle incident, as it involved manicotti, which is, essentially, a large stuffed noodle (but the Noodle Incident was mentioned many times before this strip, so this is unlikely because they couldn't refer to it before it had happened).
These are the only facts we know about the Noodle Incident:
- Calvin was the apparent perpetrator, and it must have involved noodles.
- It happened at school. Miss Wormwood evidently knows about it, and may have even been a witness to the incident taking place. This is revealed in a strip where Calvin's mother goes to a parent-teacher conference with Miss Wormwood, causing Calvin to panic when she gets home, asking her, "She told you about the noodles, didn't she?!" Calvin's mother replies with a suspicious "What noodles?", but does not press the issue. Calvin also claims he was "framed", which may indicate other people saw the incident.
- Calvin never told his parents about the incident. Apparently, Miss Wormwood and Principal Spittle never told Calvin's parents either.
- It happened a long time ago, (as revealed in a fantasy strip where Calvin is imagining Santa Claus and one of his elves reviewing his "case" to determine if Calvin has been good or bad that year) and therefore must have been a very serious incident for it to still be remembered now. The fact that Hobbes repeatedly brings it up (as did Santa Claus in Calvin's imagination once), seems to imply the memory still haunts Calvin to this day.
- Although it happened a while ago, in a strip when Calvin was mailing a letter to Santa, he said that he had been extremely good this year, to which Hobbes replies "What about the Noodle Incident?" revealing that the incident may have happened that year. However, because the strip ran over a ten-year timeline, yet Calvin remained six years old and inexplicably returned to the first grade every fall, the Noodle incident could have happened at any time.
- It is not exactly stated one way or the other, but it seems to be implied that Calvin was caught or framed, therefore his explanation was not believed (though this could simply be Calvin trying to avoid trouble). To try and prove innocence, Calvin apparently thought of a cover story, the creativity of which impressed Hobbes. Calvin, however, even now claims that it was the "unvarnished truth". Like the incident itself, we are never told exactly what Calvin's excuse was. In fact, for all we know, it may actually be the truth. According to Calvin, although apparently caught or framed, no one can prove he did it (which is also said by the elf mentioned above). However, considering Calvin may just be defensive about it makes such a statement questionable.
- Police Officers (or firemen) may have been involved, because Hobbes once asked, "Did it have anything to do with those sirens around noon?", but this is debatable because Calvin's parents never found out about the incident and they likely would have if it was serious enough to involve the fire department or the police. Moreover, we do not know if the sirens had anything to do with the Noodle Incident.
- Hobbes apparently knows of the incident. However, if police officers were involved, he was probably not at the school at the time, otherwise he wouldn't have asked about the "sirens around noon". If this is true, then it is likely that Calvin eventually told him.
- It probably involved something that is not allowed, judging by the fact that Calvin thinks he would get in trouble if someone proved he did it.
Whatever happened, Calvin was apparently forced to confess to it, as indicated in one strip where Calvin is lamenting his inability to write a fictional narrative for school. Hobbes offers, "What about your explanation of the Noodle Incident?", after which Calvin yells "That wasn't a story! That was the unvarnished truth!"