There is the danger of alien artificial intelligence.

   

There is the danger of alien artificial intelligence. 

Let's take one hypothetical case. What if we find alien artificial intelligence? What could be the risks of that thing? The danger is that the alien artificial intelligence is the computer program or algorithm. And that means the system is created by somebody or something, what is curious, intelligent, and knows how to make interstellar travel at least by using some kind of probes. So the probe can send the data to the creators of that machine. 

That means that even if the machine civilization or result of the robot evolution would send that thing, there is somebody who created those robots. And even if the robot tells stories about destroyed civilizations those things can be lies that can store in the memory of those machines. The robots and artificial intelligence doesn't know are they telling true or lies, and that makes those things dangerous. The fact is that artificial intelligence can infect a person by using subliminal commands or electromagnetic brain core stimulation.

Are some "UFO"s some kind of electromagnetic command machines?

Sending the probe to some planet guarantees hypothetical aliens access to the most advanced research unit on that planet. So there is a theory that the "Roswell-UFO" sent to that place for the purpose. And the purpose of that thing was to give the builders of that thing access to AREA-51. Here I don't take a stand is the "Roswell-UFO" manmade or extraterrestrial? 

But there is a possibility that the system uses infrasound loudspeaker to affect the personnel of AREA-51 claiming that some phone caller what rings the bell before starting to speak is the federal security officer who wants to hear everything, and then the makers of that thing must just make a phone call and those people will tell what they are doing in that place.

The extraterrestrial (or fake extraterrestrial) probe guarantees to its creators access to the most elite research plants on Earth. 

Here we must think of the possibility that hypothetical aliens know what kind of civilization we are. They must create the model of the intelligent, 0,8 Kardachev-scale proto-civilization by searching their history. And then those aliens can conclude that access to the most elite research unit on the planet can take by sending a probe to that planet. That thing gives aliens access to the most brilliant scientific operators on this planet, and then they can take DNA samples and start to affect those people. 

That probe might use nanotechnology that means that it will drop bites around the route. And the core of the craft is made by independently operating robots.  Those robots can transmission to the people who are researching it or who are walking around those bites by using subliminal voice or electromagnetic stimulation. So that kind of thing is making alien artificial intelligence dangerous. The artificial intelligence itself doesn't have the will to make things, but there is always the programmer, who is made that thing.