"You still don't understand what you're dealing with, do you? Perfect organism. Its structural perfection is matched only by its hostility.... I admire its purity. A survivor, unclouded by conscience, remorse or delusions of morality.” That is how the android Ash famously describes filmmaker Ridley Scott's extraterrestrial monster in the 1979 blockbuster Alien. The movie provided nightmare fodder for an entire generation of science-fiction fans with its tale of an alien creature that attaches itself to the face of a crew member of the spaceship Nostromo and implants an embryo that later bursts from his chest. Technically speaking, the alien is a parasitoid, an organism that, unlike most parasites, ultimately kills its host. No one who has seen the film will ever forget how it reproduces, even if they want to.