It'd be awesome if facehuggers came into a school.
Just imagine it:
A bunch of bored kids sit in front of a dull teacher, scribbling stuff on a blackboard.
All of a sudden a clattering is heard, like a rat scurrying across the floor.
A kid sticks his hand up and tells the teacher that he thinks theres a rat or something in the class.
The teacher tells him to ignore it, its more scared of him than he is of it. A couple kids giggle at that.
The kid is still uneverd, clattering noises sound every now and then, as he sticks up his hand to tell the teacher again, a facehugger leaps out of nowhere and clamps to his face. Everyone screams and more and more facehuggers start crawling in from open windows, vents, everywhere.