Fan Theories Wiki

Cancer theory

Why is Caillou bald? People have wondered about this ever since Caillou was a thing. And why are his parents always so calm? Why is he so whiny? Either his parents are obsessed with his looks, or secretly abuse him by shaving his head.

This theory says Caillou is actually a toddler with cancer. The reason why there's always a white frame border in the show is because Caillou is on his death bed and the stories are Caillou's fantasies of his ideal life or just flashbacks. Caillou's cancer could also be the reason his parents spoil him because they want to give him happy memories before he passes away and they feel guilty of punishing him because of his disease.

Or in another way, Caillou died before the series started and the narrator is simply telling stories of her grandson to the two kids.

Another theory could be that Caillou never had cancer and instead was born with a gene that prevents him from growing hair, or his growth of hair is very slow and it may take years until his hair starts growing.

Éditions Chouette have mentioned that the true reason Caillou is bald is because he originally was an infant in the books, and they wanted to keep him recognizable to children.

Furthermore, the original voice actress of Caillou,Jacklyn Linetsky, died in a car crash in 2003.

Rosie the Narrator

This theory focuses on the possibility that the narrator is actually an older version of Rosie, in which she is telling stories of her brother to her children (or grandchildren). There are numerous reasons to support this theory. Firstly the narrator is quoted as saying “this story happened when caillou was 3” prompting the fact that Caillou was indeed a real person.

Redhead Theory


Caillou Conspiracy Theory


  • Rosie. Rosie has orange hair either because she's adopted and Caillou's parents did not want to get another child like Caillou, or one of the parents was more of a redhead when they were younger and their hair became darker over time. Or possibly Rosie's "gingerness" could have been passed by her grandparents, but none of these theories have evidence.

One Punch Man

  • Did you know Caillou went to Japan and became a superhero? Caillou originally went to Japan as a businessman and failed miserably. He then defeated a villain named "Crablante" with a superhuman crab mutation which motivated him to become a hero. This lines up with Caillou's previous passion of becoming a superhero. His adventures can be seen in the Japanese anime "One Punch Man."
  • Caillou's legacy also continues. His superpower, or "Quirk" as it is called in the universe, is greater than all other heroes' or villains. A villain named "All for One" is able to subdue him and steal his "Quirk", and force it upon his younger brother to force him into submission. The younger brother opposed "All for One" and transferred it to other heroes, which lands the power in the hands of "Toshinori Yagi" and also "Izuku Midoriya" who are able to successfully able to defeat him. (See more at
  • Caillou is genuine about being a hero, not fighting for money and for fame. But fighting for his own entertainment and fighting for humanity. He shows great dedication, and excels in combat. He previously displayed great physical strength as a child which lines up with his desire to become a hero.
  • Also when translated from Japanese, one of the lines were "I once was weak but now I've grown!" This could be the follow up of "You're going to be a big boy!"

Okay, I do agree will two theories so i will make a mix up. So I do think Rosie is adopted, To replace Caillou in case he dies from Cancer.