An interesting theory I read on zombies suggests that their ability to recognize, albeit primitively, certain acts of their past lives, (Using blunt weapons, learning to open doors and whatnot.) doesn’t merely have to do with the high magnitude of their instinct and what it necessitates from them…zombies are more apt to bust through doors than to ever learn how they work…but is rather a shift of brain alteration.
If you use the Solanum Virus from Max Brook’s examples, it might only awaken that part, or parts, of our brains which are constantly dormant, for example the more primitive and physical part of our survival instinct which is currently not needed due to technology and awareness. So it doesn’t turn you into anything, rather than it unlocks that part and amplifies it to gross proportions. The bite of the zombie, the virus per se, unleashes this part of us.
Of course, that’s just a theory, but speaking realistically, that would never encompass the ability to walk as a corpse, or amass high resistance to physical damage…that is if whatever part of our dormant brain IS some survival shit…most think that it’s actually something superior than we cannot currently experience.
But maybe there’s something out there that might be able to do, more or less, what I described. Brain alteration which takes hold of your entire system. If it did, it would be the closest thing to a ’‘zombie Apocalypse’’ that I can think of, you know like cro magnons munching out on neanderthals. (Minus the nervous system hijack part.)
Massive chemical spill, nuclear devastation, a new disease, or a hybrid disease…the trick would be that it has to be ’‘contagious’’, rather than an effect which alters everyone then leaves em on their own…it’s not a zombie without the ability to disturbingly spread the disorder in a relatively short time.