@Magma Remember that time on Garfield & Friends where Garfield was sitting in the chair from The Critic and told a story about how thousands of years ago the cats committed a mass war crime on all dogs by retarding their brains
If I recall correctly he got the shit beat out of him upon leaving the studio where he was hosting this story, and rightly so. It was obviously bullshit, where Garfield was just being a dickhead for the LULZ, but like, if that was true, and I think it was hinted at it actually being the truth, then that means Garfield has exposed his entire tribe for committing an extremely heinous act that should not go unpunished. He knows, however, that nothing will be done about it, not just because all the perpetrators died having gotten away with it, but also because he himself had already long since cast aside the facade of being a mere house pet. He's hosting a goddamn documentary with a budget and actors, and he's walking on his two hind legs but no one gives a shit. It's no wonder he's got that shit-eating smirk the whole time.
I started this post wanting to just call out that the cats potentially committed an extreme violation of the Geneva Conventions on creatures that were intelligent enough to be considered sentient, but the fact that this story being true would explain so fucking much about the Garfield universe it actually makes you wonder. It certainly would explain the overt human characteristics held by most animals in the Garfield universe.
It doesn't explain things like Magic being real, as we saw in the segment where Jon took Garf (and Odie I think) to a Magic Shop to replace his defunct magician's set, but it might explain the Jupiterian Cheese Danishes, and explain why said Jupiterians couldn't detect any sufficiently intelligent lifeforms-- as we saw in Garfield's tale, the cats covered up their tracks supremely well, only slipping up when their arrogance came back to bite them. Come to think of it, it also might explain the Zizzabottawotta Boingboing Bree (I'm probably spelling that wrong, I haven't watched this show in like seven years).
Even if that was revealed to just be a dream, an entire species of Garfields coming to Earth to basically do what Garfield does is a bit interesting-- outside of it possibly being his conscience fucking with him for being a dick before taking his nap, the actual execution doesn't make sense even in the context of it being a dream unless the aliens were based on something from the real world. Dreams tend to do a shit job of representing faces that haven't been well-studied in the waking world (as does the memory bank, but same difference), so all of them looking like Garfield would make sense if these manifestations were only really there to get the job done. It would also explain why even in the world of the future the only actual faces we see and really recognize are Garfield's (because he's vain and looks at himself all the time), Jon, Nermal, Odie, Binky and that newscaster (whose face being present can be explained by Garfield's love for watching TV).