Mod parent up!
.. and if I can't have that then I'll have to settle for citizenship so that more people have some clue as to how this whole ramshackle affair actually works, or doesn't work depending on your point of view.
Maybe they just haven't looked closely enough.
That beastie in Alien, the one that was supposed to scare the bejeebers out of you as some sort of paragon of mindless violence; it's just a variant of creatures that are commonplace right here. A little bigger than most perhaps.
The face-hugger thing wouldn't raise a compound eyebrow in the caterpillar world. They face that sort of parasitism every day. And killing things and eating them as fast as you can whether they are still alive or not is standard. You only bother killing them if their wriggling might be a problem.