Hollywood loves alien invasion movies. Usually there are ships with aliens inside. These ships come down in to our atmosphere and fire weapons that look like ours, except “on steroids”.
And there are exchanges between the human army and the alien army…it looks similar to war as we know it. That’s great for entertainment value. However, an alien invasion would probably come to us in ways we can hardly imagine. I’ll try anyway.
Matrix-Borg Style: If an advanced civilization wanted to incapacitate us without killing us, this is a great option. They would simply “replace”, at the biological level, our perceived reality with one of their choosing. It would happen instantly to everyone, all at once.
Their technology would allow them to work with vast numbers of organisms simultaneously, transporting them somewhere and connecting them biologically to their technology.
The Dishonorable Route: Advanced societies may be capable of matter/energy transport. It would be a simple matter for them to transport a vital organ out of all of our bodies all at once from orbit. We would probably never see them coming. Or they could simply transport all of us in to orbit and let us burn up during re entry.
A Kind Whisper: Technological advancements could lead to something similar to mental telepathy. Advanced visitors from another world may be able to tap directly into our minds from orbit. If they had good intentions, a visitation may be very pleasant indeed.
Knowing the biology of our species and how to control the emotional aspects of our brains, a well-intentioned alien would make us feel very good about first contact. It might be a kind voice (accompanied by endorphins) that appears in all of our minds, telling us who they are. At the same time, they could share certain experiences and their intentions. This would occur in the brain of every human on the planet simultaneously. The result of this mind communication/manipulation being; an instant warmth towards, and acceptance of, these new visitors.
It is very doubtful that a visit from an advanced society would lead to any kind of drawn out conflict. It is more likely that anything they wanted to have happen, would happen quickly and without warning. One day we could all be going about our business and then an hour later a worldwide, hopefully positive, transformation has taken place…human evolution..it’s next leap, rapidly and unexpectedly.