Call them ghosts, demons, aliens, spirits, but I would like to briefly describe a direct experience I had.
When I was around 13 or 14, I remember that I was laying on a cot, in my room, on the second floor. I had a balcony and I was in a semi-awake, very fluid dream like state. Definitely not asleep. Two beings resembling grey “aliens” (who are inter-dimensional) passed through the balcony door without opening it.
Upon seeing them, I felt PURE FEAR like I’ve never felt before and then everything went black. I “woke up” later on the same cot.
This was not a dream. It seems they affected my consciousness before entering the room, putting me into a semi-dream like state.
So I have no doubt that spiritual beings, angels, demons, ghosts, exist. But they aren’t really what the movies show them to be like. They aren’t supernatural or from “outer space”. They are from other dimensions, which seem to overlay and exist simultaneously with our current dimension that we are aware of.