Ok, jokes about even more alternate universes aside, I think I have a decent concept here.
So basically, there's this house in the middle of the woods. It's been here for a few thousand years at least, and yet it doesn't look worse for wear. What's even stranger is what can be seen inside. Inside is a human from what looks like 20 years ahead of our reality, but it's been living here since 1200 B.C. The house can't be harmed in any way, and means of getting inside are completely blocked off.
The man inside can't age, and neither can anything else in his world. Technological progress is slower than molasses, and he's been using the same TV, computer, and phone since 908. Cultural progress is just as slow, with unique song's and movies only releasing once every few decades, to every few hundred years.
History and culture also seems to be shuffled, with artists and politicians who didn't even exist at the same time collaborating with one another (For example, Aerosmith and Beethoven working together to create a song).
But the main mystery of the article is based off of what actually caused this slowing of culture and time, and the side effects of whatever may have caused it, with one of the main afflictors being incredibly violent, invisible demonic entities, who attack the people of this world with such frequency that most people are used to killing them without even having to concentrate on it.
Anyway, this is my weird idea, let me know if it's ok. thank