The facehugger (which literally sexually assaults your gob and forcibly impregnates you with a baby alien) isn't the most appetising of movie villains. And the yet the ingredients for creating the effect in the original Alien sounds like a culinary delicacy, its tail being a sheep's intestine and the viscera inside of it constituting a cow's stomach, with pieces of oysters, clams and caviar. Like something Heston Blumenthal would serve. Before they leap out (using a pressurised air hose), however, and you see that bit of movement from within the translucent egg? That's director Ridley Scott wiggling his gloved hand around.