Alien mist

I wrote a huge amount about this and for some reason, I got logged out and nothing took so here is my short version: Laser/Mist-Layer - cool effect with the smoke and sound pitching as Kane moves hand closer to it. Very memorable. I wish some cutting had been done to cover up the laser's triangular dispersal pattern back to the origin so that it was the rectangular mist that they were attempting to portray it to be. Effects aside, the purpose, I think was to make the SJ crew aware of any premature hatching before their payload could be delivered. I doubt this was their first hair-brained effort at this and I am pretty sure that the SJs had many of these ships containing full cargoholds of bio-weapons heading out in all direction with thousands of years of success.

I think the blue laser was a protection for the SJ's. If you cross that blue wall, the eggs/Facehugger can smell you (or whatever).

Ok....so how come the eggs in all the other movies dont have a lazer or mist about them? Eggs dont produce lazer light now do they? Its just that it looked cool for the movie....remember it WAS 1979