[octothorp]

Originally Posted by troutman

Finished watching last night.

I don't know how to hide spoilers,

Spoiler!

but I have a theory about the monster.

Spoiler!

There were some hints that the monster is an alien in the classic sense - from another planet or star system. The scientists talked about making "contact". Also, one of the final scenes was a long shot of a very starry sky.

More likely, the monster is a being from another plane of existence, not another star. D&D mythology is full of alternate planes and dimensions - like the Shadow Plane. The monster does not seem intelligent or capable of space travel. How can it move between worlds? Why was there only one?

Regarding dimensions:

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I think the question is why the upside down seems to mirror our world geographically; there are more hints (but still no answers) in the dimension than in the monster itself. Is this an alternate dimension that at some point diverged from ours? Is it a 'future' version of ours? Is it a different dimension that ours has somehow infected? Maybe even an artificially-created dimension? Also, what did the monster eat before it got access to our dimension, because that other dimension looks pretty barren for such a voracious carnivore.