What happened to Inspector Gadget that saw his limbs and more replaced by strange devices? We never find out. Some believe he's actually an imitation of the original inspector, built to keep the legend alive.
Is Winnie the Pooh simply the delusions of a young boy's mind? Each character represents a different psychiatric condition, such as Eeyore who has depression, Tigger who is hyperactive and Owl, who's dyslexic.
There's a theory which suggests that the original Scooby-Doo series is set after an economic depression and that the villains, who would usually be respected professionals, have simply fallen on hard times.
The Powerpuff Girls may simply be representations of an unknown person's split-personality disorder. The disorder may have been triggered by a bully who is represented by Mojo Jojo, the girls' nemesis.
Ticks give you Lyme disease and there are people that suggest the cartoon The Tick takes place in the mind of a young boy who has become infected and is experiencing a fantasy in his delirious state, about being a superhero.
Dexter is just a kid, so how can he have an entire laboratory in his house? He probably doesn't. He's probably an introverted child who is simply playing out his wild fantasies in his living room. His bizarre accent is probably just creative play, too!