So I have been thinking about zombies for a year or two now. Actually, I started thinking about zombies long before that, but I am talking about zombies in the literary sense. I "wrote" a "novel" back in 2004 for National Novel Writing Month called The Nazi Zombies of Underground Louisville. (The quotation marks are meant to imply that I typed more than I wrote and the result was a fucking mess rather than a novel.) The species of zombie in the book was derived from the Romero zombie. In otherwords, it was slow, mindless, and could be killed by severe head trauma. At the time I thought I should try and come up with something more original, but since I had only 30 days to bang out 50,000 words, I abandoned creativity for speed.
Since then I have decided that the George A. Romero zombie, while perfectly fine in his movies and their rip-offs, has been done to death. And as a matter of principle, I am against the "fast zombie" featured in House of the Dead, Resident Evil, and 28 Days Later*. Insofar as I want to inject some realism into a horror genre that is fantastic by definition, reanimated corpses cannot move too quickly or they will fall apart. As the connective tissues degrade, stuff will just start falling off, like when that one non-dancing zombie's arm fell off in the video to Michael Jackson's Thriller. Plop.
And I don't want to deal with the actual zombies of Caribbean folklore. These poor creatures are real and, therefore, are less scary. Nor do I want magically created zombies, as in various role playing game and fantasy universes. In my fiction, magic doesn't exist if for no other reason than it is convenient -- too easy. I don't want to get into a flame war with any of you real-life wizards, witches, wiccans, and whatever. Regarding magic here in meatworld, my mind is wide open.
Also, I have to abandon, sadly with with much regret, the iconic image of zombies reaching up out of their graves, their hands erupting from the soil like unholy flowers. As the Mythbusters have clearly demonstrated, it would be nigh impossible for anything to emerge from a modern casket buried more than a couple feet deep. Even if you used kung fu, like The Bride in Kill Bill Vol. 1, you'd still have hundreds of pounds of earth on top of you and no leverage with which to use to dig out.
So what is left? What are the biology and physics of my zombies? I don't know for sure yet, but I have some ideas. First, there must be some biological imperative for why they exist and why they attack humans, especially to the extent that they attack humans exclusively. My first thoughts are that the zombies are host to a puppeteer type of parasite that employs the corpse as a vehicle to get from place to place and perpetuate itself. Its life cycle would be something along these lines. First, the parasite enters a corpse and begins devouring it, using it to grow. The parasite grows to form a sort of parallel nervous system with electro-chemical connections touching each of the host's largest muscles. The parasite then activates and begins flexing the muscles. The corpse, like a marionette with the strings on the inside, gets up and walks around. The parasite exudes eggs or nymphs in the saliva, and when a victim is bitten, the parasite invades another host.
Naturally, this mechanism makes killing the zombie a little more difficult than simply popping it in the head. If the controlling functions of the parasite are centralized, then destroying the "nerve center" would make sense. But to make things more interesting, why not have these functions distributed/decentralized? Hack off an arm, and the arm still wants to feed. Your choices are reduced to total disintergration (e.g., burning) or incapacitation (e.g., dismemberment, removing lower jaw.)
Another idea I had, but have not developed as fully, is what I like to call the "It's life, but not as we know it, Jim" model. (Star Trek reference == geek cred++) This model means that the normal, traditional model of "life" is radically reinterpreted. Death isn't the end of the organism -- just the soul. The organism continues to feed and procreate as a zombie with strange metabolic functions and other whacked out shit. In other words, it's like someone playing SimReality hacked the code and changed the rules mid-game. This is tinkering bordering on fantasy so I am less inclined to go this way.
I'm still thinking about all this. I just wanted to jot these ideas down somewhere.
* Yes, I know they technically were rage
victims and not zombies.