In a story I'm just beginning to write, the aliens who have invaded Earth have a ghastly secret that is about to become known: They reproduce exclusively by transforming other sapient beings into more of their own kind...
At this point, I know what you're thinking: "Isn't this just classic space zombies? Or maybe Cybermen?"
You would be right to think that at first, but there is a crucial difference here: Individuals who are transformed in this way retain their original personalities and memories; They aren't just being used as raw material to create something new, as those converted retain their selves and identities.
My question then is "How and why would this happen?" Why would this being the only way a species would maintain and increase its numbers, and by what means would it do so?
Here are some criteria answers must meet:
- The conversion must involve radical physical bodily changes; A change of identity, possibly involving minor bodily alteration, is not enough
- Those converted must retain all their original memories and something that could be recognised as their original personality; Original instincts and bodily drives may be replaced, but every aspect of a person's personality not inherent to their species should remain as close to the same as possible
- This species must reproduce in such a fashion exclusively; They cannot simply convert other species into more of their own while also reproducing in the normal way; Conventional reproduction must be impossible for them
- This means of reproduction must be inherent to the species; It cannot be that this particular culture just so happens to forbid other methods of reproduction. Note that this does not mean that the reason could not be psychological; For example, artificial beings hardcoded never to create new consciousness would be acceptable