As Micah says:
"While driving around one day I ended up playing a 'thought game' with myself where, in an effort to brainstorm ideas for short horror stories, I considered what things scared me most. The first things that come to mind for many of us involve sickness and disease, as evidenced by the growing number of films today which revolve around humankind being introduced to foreign strains of bacteria and infections, often leading to bizarre malformations and eventual death like in Danny Boyle’s film 28 Days Later, as well as the Resident Evil series based on the popular video game. But as I began to consider what really scares me deep down, I was able to relate my fears to my long-time interest in cryptozoology, and touch on something that I find both truly strange and fascinating, yet nonetheless terrifying. My own greatest fear, at least along the lines of a 'what if' basis, would have to be strange creatures living deep within the earth."
In many ways, it kind of reminds me of a number of stories I heard about ten years ago in England about wild animals roaming the darkened depths of the London Underground rail network.
In fact, I think I'm now gonna dig out my files and work on a posting on these London Underground stories for sometime next week.