Weird scenario

[-Sky-]

So lets say IT succeeds and all the world is placed under the Genjutsu. What happens when aliens invade?!

The human race would be doomed!!! : OOO

When you think about though, IT pretty much kills everyone on Earth. They'd all die from lack of nourishment and whatnot. The fantasy may last them for as long as they wish though

 

[Disquiet]

Well there's a chance Madara may keep everyone alive via the God Tree/Mother Nature. Also, Madara would most likely have control over juubi and its powers. That alone will probably be enough depending on the abilities of the aliens. There's also the chance they would fall under the genjutsu as well; though that may depend on chakra networks.