A number of soft, easily-captured-immobilized-broasted-and-eaten humans with a vested interest have been thinking, furiously it seems, about the down-in-the-weeds details of how our first contact with an alien intelligence might go. And some of our sage-est of sage elders (as in S. Hawking) think things could go very pear-shaped. Really fast.
Let’s review: first, get the in-depth overview from the boffins (love that word) at NASA and a couple of leading American universities in this exhaustive paper, with the no-nonsense-whatsoever title: “Would Contact with Extraterrestrials Benefit or Harm Humanity? A Scenario Analysis.”
For a handy general consideration of the issue, there’s this at Discovery.com: “Do Aliens Exist? If So, Will They Kill Us?” Always a pertinent question. So, you’re wondering, other than simply because they’re voracious, predatory, vaguely-insectoid-or-squidlike-bad-asses-with-no-moral-compass-and-an-appetite-for-hairless-monkey, why would any advanced, star-tripping, alien race WANT to do unto us in such an ill-mannered manner? Well you should ask. Discovery again has a nice, bite-sized (so to speak) summary for you. Turns out, there are several very good reasons an otherwise benign, enlightened gaggle of off-worlders would want to smoosh us Earthers before we spread beyond the Solar System. Jeesh. And E.T. seemed like such a swell little guy….