The Beano/WMG

The characters in the Bash Street Kids are all strange because they're insane, and they're insane because they looked at Plug's face.

 * Come on, it makes sense. In addition, Plug is insane either as a result of seeing his own face in a reflective surface, or because he can never see his face as every surface it gets reflected in instantly shatters.
 * Then how come Cuthbert and Teacher are sane?
 * Teacher arguably isn't particularly sane. He appears to be quite dotty and in one comic was shown to obey every sign he reads, so perhaps that's how his insanity manifests itself. The same could be said for Cuthbert occasionally. Or perhaps Cuthbert's insanity, like Teacher's, manifests in a different way, in this case his obsessive swottiness.
 * Do you count bad entries |the creators don't admit exist as canon? If so, The Beano Video says Plug is an archetype.
 * To be fair, the monks that are implied to look exactly like him don't talk.

Daisy in the Crazy For Daisy strips is an Unreliable Narrator

 * Basically she's a classic Tsundere towards Earnest, hence why his less reliable qualities are exacerbated (the parts where she isn't around are her guessing at what was going on). The alternative is that this is a children's comic strip about a girl with a Stalker with a Crush interfering with her life at every turn....

Daisy's surname

 * We know Ernest's surname is Valentine, but what about Daisy's? I think it's Daisy again, in reference to the love song "Daisy Bell".

Dennis the Menace is the only Beano character to age normally

 * As described on the main page, Dennis in 2015 was revealed to be the son of the 1980s Dennis. Thus it's canon that Dennis the Menace is a Legacy Character covering at least two generations. Nothing similar has been suggested for the rest of the Beano characters: they just don't age. The Menace family are the odd ones out, and try to cover it up to fit in: The oldest son is always named Dennis. From the age of about 6, his antics are recorded and appear in the Beano. He produces several comic-worthy stories per week, so the writer/artist chooses one and keeps the rest for later. When Dennis shows signs of puberty, the comic switches to those saved pre-adolescent escapades. Dennis gets on with his life, marries, they have a son, and the cycle repeats.
 * The family tradition is so ingrained that at least one Dennis gave his son "'s Dad" as middle names. His full name was therefore Dennis 's Dad Menace.
 * Shortly after Dennis was introduced, he started to grow - The Beano 50th anniversary book reprinted a strip where Dennis was taller than an adult bagpipe player (including the pipes). Out-of-universe, there's a story that Dennis was drawn more stretched as his artist became more stressed. In-universe, Dennis was turning into a lanky teen. The artist was stressed because he thought he was about to run out of material. Fortunately they were able to fill up the next few years with the help of Dennis' mum's diary. Once Dennis Jr started menacing, the editorial team decided to make him a Legacy Character.
 * In the Beano letters pages of the 80s and 90s, Dennis' age was a recurring question, and he always avoided answering. Somehow the other characters' ages didn't generate so much interest. Readers had noticed something was odd about Dennis.
 * The Beano printed two different stories of how Dennis met Gnasher. In the main strip, Dennis found a fully-grown Gnasher. In Gnasher's Tail, Gnasher remembers being found as a tiny puppy by a very young Dennis. That wasn't a Retcon, it was how Gnasher met the first Dennis he knew. Gnasher stopped ageing at adulthood and was given to a neighbour when his Dennis went to university, but when he saw how similar the next Dennis was to his father, he decided to go back to the family.
 * This troper knows an individual who was a rebellious misfit as a pre-teen, but became a studious, (mostly) easy-going teenager, inverting traditional stereotype. Dennis' family have the same trait, making each post-adolescent Dennis too boring for a main Beano character.
 * Other Beano characters must be aware of Dennis' ageing, some of them have seen several generations of menaces grow up and move on. It seems to have been kept secret from the audience for a long time, though.
 * Bea probably wasn't the first Dennis sibling. 1950s Dennis was an only child and they didn't mention the siblings of subsequent Dennises because they wanted to preserve the myth that it was all the same Dennis.
 * Bea has inherited the Can't Grow Up gene from her mother, and won't age any further. This was revealed early on by CVS, that's why they put her in the story instead of hiding her like previous Dennis siblings.
 * Sooner or later a Dennis will be born with the same trait. Eventually someone will try to retcon the rest of the Dennises and pretend they're all the same person.
 * Most of the Dennises married young. They look old from the stress of coping with young Dennis. They usually take early retirement and move out as soon as the kid(s) leave(s) home.