[[WMG: Film/{{Flubber}} is a manifestation of Getter Rays]]
It's green, sentient, physics-defying, has the ability to split and recombine itself, shows an interest in mimicing humanity, and is used as a source of power for vehicles. Not to mention it was let into the world by a MadScientist.

[[WMG: The Getter is responsible for the creation of [[Webcomic/GirlGenius Sparks]]]]
It spreads to new realities by influencing their inhabitants until one of them succeeds in creating a Getter Robo. Its pilots may also be Sparks, given that the few who can bring out the full power of a Getter tend to be mentally unhinged.

[[WMG: All versions of Getter Robo exist as AlternateUniverse versions of each other]]
Based on the endings of ''New'' and ''Armageddon''.
** Confirmed by the plot of Devolution, where a fragment from the Getter Emperor falls between universes to end up in the Devolution world and ignite the plot.

[[WMG:Alternatively, what we seen at the end of ''Armageddon'' were:]]
[[spoiler: Previous incarnations of Manga/GetterRobo, including some we had never seen]]. Some bits of dialogue seems to support that.
** This leads to theory that [[spoiler: Manga/GetterRobo Universe is resetting itself]].

[[WMG: Manga/GetterRobo Universe/Multiverse is connected with TabletopGame/{{Warhammer 40000}}.]]
And dimension at the end of ''Armageddon'' is Warp - red/purple background and monsters with human features on hon-human bodies that wouldn't stand out in Warhammer 40.000 sorta leave that impression.

[[WMG: Getter Rays are emitted by a [[Anime/GaoGaiGar G-Stone]].]]
Green, fuels a SuperRobot and makes it even stronger when the pilot goes [[UnstoppableRage completely]] [[HeroicResolve over]] [[ScreamingWarrior the top]]? Of course. Coincidence? Probably not.
* Confirmed, sort of, in Alpha 3. They, along with [[Anime/GoShogun Beamler]], Psychic Power, [[Anime/GunBuster STMC]], Anima Spiritia and [[Anime/SpaceRunawayIdeon Ide]] are aspect of Akashic records (fate).

[[WMG: Getter Rays are what happens when a universe goes full Spiral Nemesis...]]
...and the combination of all that ever lived combines inside ''inside the black hole'' into a being beyond understanding, which [[Anime/DieBuster Inazuma Kicks the event horizon open]], and does a swan dive onto another universe [[ComicBook/FinalCrisis Darkseid style]], bathing reality in its presence.

G-stones? G-stones are what happens when you take such a being (or a fraction of it, at least) and ''[[DidYouJustFlipOffCthulhu punch it in the face until it respects you.]]'' You teach it emotion, and when it understands your drive, it allows itself to evolve [[BeyondTheImpossible beyond the end of evolution]].

[[WMG: Hayato's recount on the destruction of Saotome Labs in ''Getter Robo Go'' being different from the events depicted in the ''Shin Getter Robo'' prequel isn't really actually a {{Retcon}} as much as it being technically MetaphoricallyTrue]]

[[WMG: The Getter Robo Arc 2021 anime maybe able to complete and tie up the rest of the uncompleted story]]

Jossed. Ultimately it didn't go in full detail any further than the manga, ending on a cliffhanger as Saint Dragon appears from the depths of the Saotome Laboratory during the fight between Takuma aboard Getter Arc versus Kamui in Bug. Based on what we are shown happens after the very sudden timeskip, it can be surmised that :
* Bug clashing against Saint Dragon caused either the outright destruction of the Earth, or made it impossible to sustain human or saurian life, thus starting the journey of humanity through the stars. Just as Getter Emperor had planned.
* Kamui ultimately got defeated and was made responsible for the whole debacle, leading to him being jailed on Mars where the survivors of humankind and saurians emigrated.
* Baku was shown to have premonitions of the future, and it could be explained by Getter Emperor being a singularity spanning multiple universes and the timeline where it exists/will be born. Therefore, his premonitions could be seen as a byproduct of the Getter Rays [[StableTimeLoop nudging him in the right direction to be born and ensure the singularity is formed]], since Getter Emperor remembers events.
** However, as stated, it doesn't remember the events after Shin Getter Robo got sent to Mars, meaning the gap in the memories might be a chance to avert the BadFuture. This has to be where Arc comes into play as trying to fight the nascent Getter Emperor (confirmed to be so, since it evolved on Mars and speaks in Ryoma's voice).
** Therefore, one can surmise Baku tried to understand better Emperor to understand how to influence it since it's neither good nor evil.

It would have been nice to have the full story spelled out, but we can piece the above together based on what elements we have been given.