WMG: Oggy and the Cockroaches

The cockroaches are in Hell.
Think about it. As shown in the opening, they got squashed by the falling brick. Throughout the series, they managed to come back to the life of the living to make Oggy's life a living hell. In some cartoons, Oggy manages to use the punishment against them. Therefore, the cockroaches' hell throughout the series is ironic.

Naturally.
  • Jack: becomes much more famous in what he does more than caring the life of Oggy, and will be subjected to torment by the very thing he becomes successful at.
  • Joey: he's the one who tries, tests, and torments other characters.
  • Oggy: sent to an Ironic Hell to being the lazy bum that he is. He is forever lazy and never be satisfied.
  • Bob: his anger has lead him to be subjected to every torment that Oggy, Jack, and the cockroaches throw at him.

The cockroaches are actually Ed, Edd n Eddy, who were transformed into cockroaches.
They look very similar, and it makes a very good Fanfic Fuel.

The series takes place in the same universe as Zig And Sharko
Both shows are property of Xilam, sharing identical animation styles. Both have characters who rarely use dialogue.

The cockroaches are physical manifestations of Oggy's Id Superego And Ego
Really, think about it!

Elmore is the future state of Oggy's hometown, and Gumball is Oggy's descendant.
Here's the possible events: In the present day, anthropomorphic animals like Oggy exist alongside humans, but they're not very diverse, with Oggy being one of the very few, with a few hints of unusual stuff. Several years after that, animal society becomes more common, along with objects and other stuff, and are more accepted by the humans, with unusual stuff becoming more clear. Regular Show takes place around this time. Eventually, humanity slowly become less and less common, with animals and objects becoming more and more dominant, and their city is eventually known as Elmore. Throughout all that, Oggy's family line gradually looks less and less like him until it ends with Nicole and Gumball, who looks barely like their ancestor Oggy.

Alternatively, Ooo is the future state of Oggy's hometown.
Think about it. Several episodes of Adventure Time shows modern-looking ruins and artifacts, possibly implying Ooo may be at least similar to modern-day earth in the past. Also, several episodes of Oggy and the Cockroaches show the existence of magic. Considering all these hints, it's possible that The Land of Ooo is in fact Oggy's hometown in a very far future...