I decided not to bother to include a separate read-alikes/watch-alikes list, because I could barely think of anything to list. A couple I'd suggest, however, are The Matrix (the robots are significantly more sinister than the spiders, but the result is similar) and A. Lee Martinez's Emperor Mollusk Versus the Sinister Brain (more B movie sci-fi than literary sci-fi, but, like the spiders, Emperor Mollusk has a huge amount of influence and tends to ride around in a fake body).
Review:
It all starts with a wasps' nest in Raymond's mother's basement. The wasps are Hymenoepimescis sp., which usually reproduces by attacking the Plesiometa argyra spider and laying its eggs within the spider's abdomen. As the larvae feed off the spider, they change its behavior, compelling it to create a web that can allow them to finish their development. When the spider is done with its work, the larvae kill it. (The spider and wasp species are real – nature is freaky and horrifying.)
Hymenoepimescis sp. doesn't usually build a nest or use humans as its hosts, but in this case it was affected by the unusually high radon levels in Raymond's mother's basement. Julia, Raymond's wife, is attacked by one of these wasps and unknowingly has its eggs injected into her. Over the course of the next few months, the larvae gradually affect her behavior in various ways, until one day she decides to leave Raymond. From that point on, she proceeds to become famous, carrying out an assassination and inspiring a nameless political movement which has no apparent goal. What neither she nor Raymond realizes is that they are both pawns in an ancient war between Hymenoepimescis sp. and Plesiometa argyra.
