Well, I remember a type of space robot/computer that thinks humans are brutal species and should be eliminated. It could be argued that it isn't alive so it doesn't understand that humans have the capacity to learn and grow, but then some sentient species must have programmed it in the first place. Unless the computer gets infected or otherwise has developed its own consciousness and takes over...

Fanfiction and fandoms are fun when I'm only consuming content. ;) But I'm happy and grateful that not everyone thinks the same, otherwise there will be no fanfiction for me to read at all.

I'm not too sure about the aliens being nice. ^^; If they want to kidnap humans, surely they need spaceships that can accommodate humans (or otherwise can shrink them, which happens sometimes).