Egg

The egg is the first stage of a Xenomorph. It is laid by the Queen. Inside of an egg is a facehugger. Drone aliens, take the freshly laid eggs from the Queen, and put them in front of a trapped host, so the facehugger has one when it hatches. Eggs aren't the most interesting stage of a Xenomorph, most definately. One thing that confuses me, is that when Kane was investigating the eggs in Alien, thee was no Queen, and the eggs were transparent. Also he noticed a blue film covering the eggs. In all the other movies, the Queen is always with her eggs, the eggs are a more brown colour, and there is no blue film covering them.