A character in fan fiction (typically the author themselves) who is inserted into an existing universe and is unrealistically perfect. A fan-fiction version of Mary Sue: A term for a character who is unrealistically perfect without any flaws in (original) novels (Male of Mary Sue: Gary Stu)
"When she wrote herself into Harry Potter as the best witch ever, becoming the headmistress of Hogwarts while being a student, defeating Voldemort with itching powder and a single sponge, she created a canon sue."
by DictionaryDecimator July 6, 2024

Basically when something Fanon like a theory, character, idea, etc gets introduced to a fandom that people think that the Fannon character, theory, idea, etc is canon. Hence the name CANON FANON EFFECT. A "canon" theory, character, etc.
There are two variations to look at this effect. Oblivious or Disregard
Disregard: When people are aware that this character, theory, idea, etc isn't canon. But treat said character, show, theory, idea, etc as if it was canon.
Example: The Creepypasta Fandom often draws Slender man with the operator symbol in the background or most times anything really related to Slender man and sometimes even referrers to it as the operator. Even though the fandom knows that the operator and Slender man aren't the same entity.
Oblivious: When someone isn't aware that said idea, theory, character, etc isn't canon.
Example: The Creepypasta fandom thinks that Eyeless Jack has an origin in which he was used in a sacrifice to become a monster. Even though he never had an origin, to begin with.
There are two variations to look at this effect. Oblivious or Disregard
Disregard: When people are aware that this character, theory, idea, etc isn't canon. But treat said character, show, theory, idea, etc as if it was canon.
Example: The Creepypasta Fandom often draws Slender man with the operator symbol in the background or most times anything really related to Slender man and sometimes even referrers to it as the operator. Even though the fandom knows that the operator and Slender man aren't the same entity.
Oblivious: When someone isn't aware that said idea, theory, character, etc isn't canon.
Example: The Creepypasta fandom thinks that Eyeless Jack has an origin in which he was used in a sacrifice to become a monster. Even though he never had an origin, to begin with.
Guy1: Hey man your drawing sans eye wrong. It supposed to be glowing with a flame.
Female1: Actually sans never had shown to have a glowing or flaming eye, just one that switches colors really fast.
Guy1: Wait, really? then why does the fandom draw it whenever he's mad or using gaster blasters?!
Female1: Must be the Canon Fanon Effect.
Female1: Actually sans never had shown to have a glowing or flaming eye, just one that switches colors really fast.
Guy1: Wait, really? then why does the fandom draw it whenever he's mad or using gaster blasters?!
Female1: Must be the Canon Fanon Effect.
by Mcfat10 March 28, 2020

Not necessarily canon, but canon in your own perspective. Your own alternate perspective of what’s canon.
In my head-canon, Mario in the original Donkey Kong games from the early ‘80s is actually the father of Mario and Luigi. That Pauline is probably a different Pauline. Maybe it’s modern Pauline’s mother. The second Mario in Donkey Kong Jr. is Mario and Luigi’s random uncle.
by AntiCircumcisionMan March 19, 2023

A canon pairing in fiction is a couple accepted as official by the author and a large part of the fanbase.
by Lahavas October 27, 2021

just the best person not 4"1 or stupid and is way beter than chris and is better than chris at everything else
Person 1: Dude I just saw a little chocolate cupacake who tripped on her own shoelace and accidently KILLED five babies!
Person 2: Oh yeah! that was chris, he just sucks at everything and is not like Chayse canon who is cool beans! chayse is cool
Person 2: Oh yeah! that was chris, he just sucks at everything and is not like Chayse canon who is cool beans! chayse is cool
by chayse canon February 14, 2023

A significant moment or event in ones lifetime crucial to their character development. These events can have both good and bad outcomes.
The term originates from the 2023 film "Spider-Man: Across The Spiderverse," where several examples include getting bitten by a radioactive spider, Uncle Bens death, the death of a police captain close to Spider-Man, among others.
The term originates from the 2023 film "Spider-Man: Across The Spiderverse," where several examples include getting bitten by a radioactive spider, Uncle Bens death, the death of a police captain close to Spider-Man, among others.
by Massacre_All_Furries December 7, 2023

When you take a wet shit on the ground, shovel it up, mix it with bananas and peas in a blender and then shoot it up your girlfriends ass, just to suck it back out with a straw. Then get your girlfriend pregnant.
I went to my girlfriends house and performed a fierce DIRTY CANON on her.
After doing the dirtiest of DIRTY CANON’s, I had to make a sudden trip to the ER.
After doing the dirtiest of DIRTY CANON’s, I had to make a sudden trip to the ER.
by Mosart May 10, 2020
