What if
1. Movieverse - Role reversal AU:
Sam has a problem. He has a crush on Mikaela, the cutest femme on his school, but unfortunately, Mikaela has already a mechfriend called Trent. But there could be solution. If Sam gets one more A his father is buying him a human and the best way to get a femme is a cute, little, well-cared for human. Sam gets his human, a Youngling with blonde and black hair, mute but so cute that he will win Mikaela's power core effortlessly.
What Sam does not know, is that there's more to his little pet than meets the optic.
Basically the plot idea is to make Sam, Mikaela, Lennox and all the other humans into giant robots. Humans are their beloved pets, intelligent to a degree (some can even speak a few memorized sentences), useful and with such a good influence on their masters, that the vehicle modes of their masters usually have a cockpit of some sorts to keep them around, even the military machines (they are more calm and focused if they have their pets with them).
The Cybertronian in turn are a partly organic, partly energy based species with the ability to copy each organic species to some extent, just their Spark staying always the same. They are more intelligent than the average human, can survive a lot more and, as they later find out, can short-circuit every machine they touch - including the robots.
What will they do in the end, after they have realized their true power?
Will the Autobots still help the terran robots against the Decepticons, or will they turn on them, to help the humans, who could develop into the dominant species of the planet if given the chance? After all, shouldn't they help their enslaved fellow organics?
2. Movieverse AU:
In the ruins of a former city of Cybertron, two groups of Younglings are playing. One group is lead by Megatron and call themselves "Decepticons" the other is lead by his younger brother Optimus and call themselves "Autobots".
They have little fights, play each other pranks, whatever you can think of, and at the end of each day, they separate and go home, telling their Creators about all the fun they've had.
One day, a strange space ship is landing. The humans have managed to destroy their own planet and now the last refugees are sturggling to survive and to find a new home. Either they see this new home in Cybertron or they want to trade something for materials, or they just want to discover what's on this strange metallic planet, but in the end, they come face to face with the Younglings.
a) Not knowing that those strange, human-sized robots in front of them are only the children of their species, the humans think that the "war" between both "factions" is actually real and the Younglings have way too much fun with their new alien friends to tell them otherwise. They use their comlinks to plan each new move, quickly settling who's the bad guy and who's the good guy in their new "war". Chaos ensues until a real adult comes to look why his Creations haven't come home for several days.
b) The Younglings have no Creators anymore, they are all what's left after a war that has destroyed their whole civilisation. War is the only thing they now, so naturally it had found its way into their games.
What will the humans do if they ever figure this out? Will the try to raise the Younglings and every other Cybertronian child that may still play among the ruins of their civilisation in exchange for a place to stay? Or will the Younglings have to grow up even faster and to learn to work together, because the humans turn against them and try to kill them to take over their almost deserted planet?