There is no other monster more contested than the zombie. Call any creature which doesn't adhere to strict Romero-style zombie epistemology - it runs, or it's not exactly dead, or it can talk, or whatever - and someone will jump down your throat. I tend to take a functional definition of your fictional monsters, meaning I'm less interested in static attributes, and more interested in how those attributes are deployed in context. Meaning if it walks like a duck even though the text calls it a chicken, you might as well treat it like a duck in terms of how that fowl functions.
Take, for example, the vampires in Twilight. There is very little to the creature called vampire by Meyer that adheres to the folklore. They're undead, and contagious, but they sparkle, cross running water, and can go out in sunlight with no deleterious effects. (I'm not even clear on whether they drink blood, or if they consume flesh too.) No one questions whether they're vampires though, because the whole functional definition of a vampire has to do with predatory aristocracy, sexual and class politics, and certain kinds of body horror, especially as regards to procreation. (Maybe this last isn't in the traditional folklore, but since Claudia in Interview with a Vampire, it's definitely a thing.) Her vamps are just ducky, even if their attributes are only vampish.
But call the creatures in I Am Legend zombies, and you will get into serious trouble with the neckbeards, even though they (the zombies, not the neckbeards) adhere to the functional definition of the zombie. They're relentless; they outnumber "normal" humans (the opposite is almost always the case with vamps); they presage or have caused the end of the modern world; their body horror is not based on their sexual attributes, but on revulsion and rot. (Also, bearing in mind I'm talking about the Will Smith and Vincent Price films, not about the source novel. Those creatures are an interesting inversion.) Additionally, those movies have lots of the motifs of a zombie narrative: besieged homesteads, traumatic loss of loved ones, the slow madness of the lonely.
I guess my point is this: I've gotten into a lot of pointless, stupid arguments on these here Internets about the definition of the zombie, and I wonder why the definition is such a big deal to people. I wonder why people police that definition so narrowly. My pet theory is that zombie narratives are often about race and class, and we're all pretty kinked about those definitions as well. Like when I see idiots say things like "Obama is half white, so I'm not being racist when I say this racist thing about him." Race isn't like swirl ice cream, but a complicated slurry of competing functional definitions. In other words, race can't be defined by attribute; it can only be defined by function. But holy god do we want it to be defined by attribute in our biologically deterministic little hearts. Ditto zombies.
But pet theory aside, I think the other things about zombie stories is that they are new on the scene, relatively speaking, so they have a kind of same-same to them. Although the whole sexy aristocrat thing is new to the vampire - older folklore has vampires as more zombie-ish ghouls who are decidedly unsexy - the folklore is old enough to allow wide latitude in definitions based on attribute. We've got at least a hundred years of sexy aristocrat blood-drinkers. You can date the modern zombie to Romero's Night of the Living Dead, no question, which was filmed not long before I was born, cough cough. The motifs have yet to fully differentiate through a century of reiteration and reimagining. We're still working out the tropes, collectively.
Which is why The Gospel of Z by Stephen Graham Jones is notable. No, the zombies are more or less your granddaddy's Romero zombies - neckbeards take note - but there's a fundamental weirdness to the proceedings that stretches the motifs, moves the markers, and fucks with the same-same. It's ten years after the zombie apocalypse - or zombie apocalypses, as the end of the world was a slow, bleeding affair in this this novel, a series of last nights before the very last night. We pop into the life of the "more or less white" Jory Gray, low level schmuck who lives in the militarized encampment of what's left of half of humanity. His girlfriend left him recently for the Church on the hill, the other half of what's left of humanity.
It's whispered by the working stiffs that the Church both worships and has neutralized the zombie threat, but this is the kind of whispering that occurs between all working stiffs, and it's both envious and disbelieved. Jory works building Handlers, a kind of superzombie built out of mad scientry and bureaucracy. The Handlers are used to differentiate zombie flesh from the edible, human kind, scrambling in the dirt to eat our remains unless our remains want to eat right back. They're also fucking terrifying, in a way, this barely restrained weapon used for the most prosaic ends. Everyone can see how they're going to go wrong, and spectacularly, but everyone is just some asshole trying to get by.
Everyone is shades of Jory Gray, trying hard not to be noticed until they are, and then fuck, maybe I'll have to come to terms with that thing that one time. Maybe the apocalypse has more to do with one moment with a hammer than it does with anything that goes on later. Maybe we're all working though that one trauma, and the zombies and superzombies and everything else is a memento mori, but a memento mori with teeth and a descant. Jones's prose is nasty, pointed, that kind of horror writing that runs everyday until it escalates, and then it's well over the fence. Catch up; keep up.
I thought the climax was confused a bit - what the fuck was that one thing - but the parts that ran everyday honestly wrung me out. So much of the end of it all is the end of the one true thing, the thing you keep trying to find once it's lost, and when you find its reminder, you sit on the floor of the bedroom and weep. You kill something with a knife made of bone. You go to work everyday like a schmuck, because that's what you've got in you. That's the only thing left, until it isn't. Who even knows.
The Gospel of Z feels non-functional, in a way, this fucking weird, armadillo-ridden narrative, too personal, too specific. This is something left out of the canon: a side story, an apocrypha, a letter to the Galatians. This is a vision on the road to Damascus brought on by epilepsy. This is a parking lot with a good vantage. Which makes it somehow perfect for the zombie narrative, giving you good, Romero zombies that no one could argue to do this crazy thing on the edges. God bless, and good night.