We all probably wonder about alternate dimensions, but what if I told you we all have our own pocket dimensions? Also think about this: we talk about having bad dreams all the time yet we never wonder why. My theory is that our pocket dimensions are somehow connected with the so-called dream world. Have you ever thought about the fact that we humans are able to lucid dream? We control what goes on in our pocket dimensions through lucid dreaming! This brings me to another point, if you know what an object looks like and how it functions, you can essentially "spawn" it in your dimension. Here's an example: have you ever had a bad dream, and then thought of a weapon, and suddenly it's there? That also explains why we can't bring sentient people into them, the only people we can bring into them won't be completely sentient, you can control them with your mind. So that is my theory, hope you enjoyed!