|A larval alien emerges from its human host|
The animal in question is a merely science fictional one, but it’s clear somebody involved really enjoyed earthly wildlife—particularly the parasitoid insects. I wrote about the life stages of certain parasitoid wasps in The Red Hourglass and again in this essay on the things I found in an elm tree:
Secrets of the Siberian Elm Part 1
Secrets of the Siberian Elm Part 2.
Here's the species of parasitoid wasp from my elm:
In the movie, the Alien goes through an insect-style metamorphosis. From a sort of seed pod or oothecum emerges a larva that attaches itself to a man’s face. It inserts a tube into his gut through his mouth to feed itself. The next larval stage emerges explosively from the man’s abdomen. Because we see the events only from the point of view of the clueless humans, it’s not clear exactly what mechanism the alien used here; possibly it emerged from the exoskeleton of its earlier larva and crawled into the man’s stomach, or perhaps the two larval stages are actually separate individuals, one the parent of the next. That second possibility isn’t too far-fetched. Some earthly Cnidarians progress through a similar cycle, with different individuals taking on different stages. (Cnidarians include jellyfish, sea anemones, and the like, but not all of them have that kind of life cycle.)
The final, adult stage of the alien seems to nourish itself by predation before laying its eggs. I suggest it may have raided from the ship’s stores as well. It pretty much had to, actually, because only five humans fall victim to it, and it doesn’t even eat them all; it uses at least some of them as fodder for its parasitic young. (Here's a deleted scene of Sigourney Weaver discovering the larder stocked with humans.)
Besides the real-life habits of insects, it seems to me that Alien draws on two interesting sources. One is a 1958 movie atrociously titled It: The Terror from Beyond Space. Same feel: a sweaty, claustrophobic spaceship. Same premise: a small crew picked off by a dangerous alien. This one is a sort of reptilian vampire. An animal with an alien biochemistry is extremely unlikely to find earthly blood digestible, of course, but the writers of It apparently didn’t know that. Neither did H. G. Wells, actually; he used the same gimmick in The War of the Worlds.
The other possible inspiration is the Doctor Who story The Ark in Space, written by Robert Holmes. Holmes’s Wirrn appear in several metamorphic stages, are parasitic on humans, and, in adult form, look a lot like wasps.
|The Doctor and Sarah Jane examine a dead Wirrn|