Lauren Faust. Go Nagai. It is unknown which of these creators would win in a Reeses Peanut Butter Cup eating contest. It is my opinion, however, that their creations, namely the ponies of Equestria and giant super robots, go together like chocolate and peanut butter.
The terrible Doctor Tartarus wants to rule the world, and only Professor Celestia and the brave ponies of the Harmonic Research Institute stand in his way. Bent on the total annihilation of all who resist, the twisted draconequis sends forth his villainous lackey, the dreadful half unicorn/half pegasus Princess Trixie Dust, at the head of an army of giant robot monsters. It's up to the Institute's mighty robotic guardian, Marezinger Z, piloted by the brash pegasus Rainboji Dash, to save the day and defend Equestria and the world.
Please enjoy.
I'm not sure what to think of this. It seems a bit crazy. I'm not sure if i should read it. But you wrote Earth & Sky. I LOVE Earth & Sky. I guess I will be reading it.
Besides, i'm a lifetime anime fan and have a really old Mazinger graphic novel mixed in with all my manga. So, even though i'm not sure about this, sometime you just gotta take a chance. 
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The crazy is a feature, not a bug. This isn't meant to be taken seriously.
How do you put Rainbow Dash in Mazinger Z with no Jet Scrander?
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Jet Scrander came along several episodes in, and not when Mazinger fought Doublas M2 and Garada K7.
Dash is pretty much playing the dual role of Koji AND Hover Pilder in this, what more do you want?
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A Rainboom Punch.
I would also accept a Sonic Raincutter.
You know I'm just funnin', right?
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Well, maybe those upgrades will come if I ever do a Great Marezinger.
The fun has been doubled!
3075540 But wouldn't that mean there'd be another pilot at the helm? I doubt anypony could measure up to whatever bar Rainboji Dash will set.
For that matter, would you go with something like a... Griffondizer or Marezinkaiser for a third fic?
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Honestly, I'm not as hip to Great Mazinger as I am to Mazinger Z. Yer right, though, they rotated Koji Kabuto out for some other guy. So I guess maybe Cadance would be a a good candidate.
In further honesty
, this was only meant to be a light, goofy one off. Not everything needs to spin off into a FoE sized fanfictional megaplex. 
3075881 Maybe so, but more robo-butt kicking's always a good thing, right?
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Indubitably!
Now I'm wondering what Mazinkaiser would look like and what the Kaiser Nova attack would be named.
A shoutout to a fellow mecha fan, heh
"None of my uncles are named Bob..."
Nice. Mazinger was kinda silly wasn't it. I will admit when Appleboss and her siblings ran off I thought they were gonna get their Getter machines actually. As you can guess I never saw Mazinger.
One of those things that just had to exist. Thank you so much.
Lol, Rainbow Dash being as hot-blooded as Kouji in Marezinger.
Who said that ponies and giant robots don't mix?
As long time fan of Mazinger Z y and fan of MLP I can say. I absolutely enjoy, tus fic.
And made me nostalgic.
This is terrible beyond belief and I love it.
Pure. Freaking. Win!
Next up: Space Cruiser Yamareto!
so, uh, since no one has said it yet...
MAJIIINN GOOOOOOOOOOOOOO!!!!
How dare you call this a Go-Nagai crossover, there's sex and boobs needed! :(
(Really the man's a perv).
https://www.youtube.com/watch?v=qcycAKDzOPQ
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Because it's just as much a Pony crossover and I don't write that kind of fanfic.
I'm well aware of Nagai's propensities. Seeing Aphrodite A fire her missiles even once tells you all you need to know.
That being said, Mazinger Z was a kid's show and they toned it waay back. This ain't "Violence Jack" or even "Cutie Honey".
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And the less said about Devilman (90's OVA and "crybaby") the better.