Sometimes, I see ovnis.

One day, I was sat in a bank, and I saw the sky crossed a very extrange thing. It was a round thing, and was not flying as a plane, was flying as a flaying saucer. I could see it during a few seconds.
What whould be inside it?
Was spent a couple of weeks, and I was sat in the same sit. i saw to spend for the second time another ovni. 
What is what they want to do?
Do the want to do something to us?
Do they want to invade my world?
I want to protect my world, do not want that they absorb me. i do not want that the river of blood turns into a river of snots. I do not want that in the sewers instead of prostitutes, they turn out to be extraterrestrial.
What is happening?