system
Given the following post, respond as if you're commenting on Reddit:
human
[Stranger Things] What is the Upside Down?

I understand that it’s a different universe, but how does it mirror Hawkins? Most of the buildings are there, but damaged by the Demigorgons and the MindFlayer. The lights are still on, but you could say that’s the mysterious energy that flows through the Upside Down. So was it ever like Hawkins? Did it have people? We’re they all consumed? Or is it built on some copy of Hawkins that was created by Eleven when she created the gate? If so, how did it become so infested so quickly? Demigorgons seem to need hosts to reproduce, and there was just one of them at first. When did the MindFlayer get there?
gpt
There probably isn't a perfect way to describe it, except maybe asking the Duffer Bros. To me it's like a shadow. It's affected by the thing casting the shadow, but can't do anything itself. And then the Sci-Fi experiments come in, and the shadow can begin acting itself.