Everybody likes a good zombie game, but I can say with confidence that nobody likes a good zombie. They make all kinds of uncomfortable groaning noises, smell of rotting flesh and show a general disdain for personal space. Luckily for us, zombies remain firmly in the realm of fiction, with only Doomsday planners storing obscene amounts of loo roll and Heinz baked beans in case the undead descend upon us.
However, some of the theories posited by videogames for how your chirpy postman could suddenly start lusting after your internal organs extract elements of scientific fact, or have commonalities with real-life medical conditions which are a little too close for comfort. We already know that fully intelligent specimens of the human species are more than capable of turning on each other, so what would be possible if our brains were flooded with bacteria or parasites?
Warning: I would not advise reading any further if you are of a sensitive disposition or are currently eating a big plate of spaghetti bolognese. Also, I am aware that some of the creatures mentioned below are not technically "zombies" but you try coming up with creative synonyms for walking corpses.
1. Kuru - the Dead Island series
The Dead Island series takes a particularly tropical approach to ringing in the apocalypse, and befitting its location, it uses tribal practices as the basis of its zombification lore. In the game, the infection was initially started by cannibalistic rituals of locals, with the consumption of infected brain material kickstarting a wider, more easily spread infection.
The eating of people's brains as the start of a zombie plague, rather than as a consequence of it, is quite a novel concept. This makes it all the more shocking to hear that the spread of neurological disease through eating brains is a phenomenon that actually exists in the real world.
Kuru is what is described as a prion disease, in which a misshapen protein strand in the brain causes other proteins to fold incorrectly, leading to the development of holes in the brain. The Fore tribe of Papua New Guinea were one of the only groups to come down with this illness in significant numbers, because of their practice of consuming brain matter of the dead (including the infected dead).
Kuru belongs to a wider category of prion diseases, including a disease which was seen in the Western world. Variant Creutzfeldt-Jakob disease, or vCJD, was seen in a number of highly concerning cases in the UK due to the consumption of infected beef. It led to a mass panic in the consumption and exporting of beef from the UK in the 1990s.
Because you can have a few malformed prion proteins in your brain for years before degeneration becomes evident, and blood tests for vCJD are not widely available just yet, it has led to many countries banning those who lived in the UK between 1980 and 1996 from donating blood.
It wasn't just the UK that saw cases of vCJD - above is a map showing the countries which were affected.
So, why does this stop short of causing mass hysteria? Because neither kuru nor vCJD turns people into red-eyed beasties who crave human flesh. Instead, both are absolutely heartbreaking illnesses more in line with dementia. The symptoms of both are tremours, loss of control over emotions and eventually complete loss of bodily functions such as movement and the ability to swallow.
Furthermore, prion diseases are not airborne or waterborne, but rather occur from consuming infected organic material, so the idea of a pandemic is extremely unlikely. Prion disease is not something to be afraid of, but rather something to be incredibly sad about.
2. Brain fungus - The Last of Us (and Resident Evil 7)
During a more precious time in my life, I was only afraid of mould because of what it could do to my lungs or to my security deposit. Thanks to the twin horror experiences The Last of Us and Resident Evil 7, I now have to worry about spores seeping into my brain matter, too.
The Last of Us provides the scientific fodder for my fear, while Resident Evil 7 enhances the fact that mould zombies would be absolutely terrifying. Naughty Dog based their zombification theory on the ophiocordyceps unilateralis fungus, which invades its host. A human infected by such a fungus would become incapable of functioning normally, being unable to make complicated decisions, act rationality or know that eating family members is a Very Bad Idea.
Combine this with how we see mould grow in the open - latching onto any moist surface, leaching its nutrients and mutating into a furry, boggy mass - and you would be daft not to wet your pants at the prospect of a mould man trying to munch on your intestines.
So why does this stop short of reality? Well, the ophiocordyceps unilateralis fungus indeed occurs in nature. However, this "zombie fungus" only infects carpenter ants, and stating that something which infects ants could very well infect humans is a huge leap to make (even if other diseases have bridged the gap between different species).
It has parallels with tabloid newspaper hysteria about particular types of food causing cancer. For example, there is evidence that excessive consumption of soy can accelerate cancer growth in mice, but no medical expert is rushing to insist anyone with a clean bill of health should consign tofu to the bin. There is still a layer of fantasy to the idea of a zombie fungus enslaving us humans, fortunately.
3. Parasites - Resident Evil 4
Many of us aren't the biggest fans of creepie crawlies, and even less so when they're creepin' and crawlin' around inside our bodies. This is a crude description of a parasite, which invades its host to obtain nutrients and then escapes when it has had its fill. This is exactly what happens with Las Plagas in Resident Evil 4.
The bastard lovechild of a Xenomorph and a headcrab?
Parasites are quite obviously seen in the wild, in humans and in animals. Tapeworms are relatively common invaders and live in the gut, resulting in increased hunger in the host. If left untreated, a tapeworm infestation can lead to cysts on the brain, resulting in neurological symptoms years later when the cysts begin to shrink. Other parasites do indeed burrow into the brain and result in related damage, including blindness.
All of this is completely horrifying, and parasite-related theories are the ones which would keep me awake at night. Theoretically speaking, they also leave room for a level of sentience in their host, which is portrayed in Resident Evil 4 very well.
This sentience includes being able to wield admirably heavy weapons.
So, why am I not on a constant course of deworming medication? Because the idea of being out of control enough to attack indiscriminately, but in control enough to follow orders, doesn't really square with any pathology model.
Frontal lobe damage can indeed lead to people being more volatile, and a parasite may lead to people being hungrier than usual. However, just the right combination of damage which leads to insatiable hunger and/or a craving for violence, while the host is still able to walk and formulate plans, is highly unlikely. It is even more unlikely in large numbers, and it certainly would not happen at the overwhelming speed required for a full-on outbreak.
In short, the parasite model is so over-the-top in its horror that it would make Eli Roth blush.
4. Viral damage to the frontal lobe - earlier Resident Evil titles
It is not difficult to spin a horror story out of a viral strain. You only have to look to the widespread panic during the early years of HIV and during the bird flu/swine flu/ebola crises to know that there would be complete pandemonium if a zombie outbreak was viral in nature. Depending on the fragility of the virus, it could even be airborne, in which case we'd pretty much all be goners (unless you happen to have a gas mask stashed under your kitchen sink).
The t-Virus in Resident Evil works by damaging the hypothalamus (leading to a flood of hunger-related hormones) and other parts of the brain in a live recipient, and generating activity in the brain stem of the infected dead. The virus can be transmitted via drinking water or through bodily fluids, such as being bitten by an zombie.
Related viruses, such as the G-Virus, are more fragile in nature and so cannot be spread through water, instead being injected directly into the host. Primary infection then leads to gruesome disfigurement, superhuman strength and the decidedly icky ability to infect others through implanting "embryos" into them. Combine this with the fact that it can be difficult to develop all-encompassing viruses for vaccines and I'm shaking in my boots.
However, something doesn't quite add up with the t-Virus (the G-Virus is so far-fetched that it doesn't even merit an explanation). The idea that the most basic of functions which are switched back on in the reanimated brain would include being able to walk and swallow is quite silly.
Unless humans are cutting off chunks of themselves and ramming them down zombies' throats, you would think those infected by the t-Virus would waste away to nothing pretty quickly and pose about as much danger as a litter of angry kittens.
Oh, William. You used to be so handsome.
5. A curse - the Forbidden Siren series
A slice of spooky folklore is the perfect accompaniment to making yourself sick by gorging on Halloween chocolate. It's not so fun when it involves relentless, murdering spirits who can never be put to rest. It really goes down like a fart in a lift when you see these spirits being depicted in skin-crawling fashion in a game.
The shibito in the Forbidden Siren series are created by townspeople following a ritual which involves bathing in infected red waters. The resulting monsters have grey, distended skin, a maniacal grin and sometimes a desire to unload two barrels of a shotgun straight into your player-character's face. While they are more like ghosts than the creatures from George A. Romero's films, they are 100% undead and are very much out to get you.
In Japanese mythology, there is indeed a spirit known as a shibito-tsuki. It invades corpses, turning them into remorseless eating machines until they collapse into a river of corporeal goo.
A face that only a mother could love.
Ghost tales and myths have always got under my skin and there's no real logic behind this. I grew up reading Horrible History books on Ancient Greece and Rome, societies which are steeped in fantastical stories. These were of course child-friendly, and so the more adult, horrifying fables interest me but shake me to the core.
Hence, while creepy Japanese folklore feels somewhat realistic to me, I don't expect anyone else to think shibito are realistic. Nevertheless, I am still a little creeped out by the prospect of swimming in murky bodies of water.
Honourable mentions: Stubbs the Zombie in Rebel Without a Pulse (peeing into waterways), The Evil Within (conjured in the mind as a torture device).
Dishonourable mentions: the Dead Rising series (bees?!?!?!), the Walking Dead series (something that everyone has in their body, which "turns" them when they die).
Which of these videogames chilled you to the bone because of the realism of their zombification theories? Are there any other games which made you think a zombie apocalypse could happen one day? Let me know in the comments down below!
EDIT: many thanks to Flegma for correcting my wording regarding prion diseases; mutated prions don't multiply, but rather cause healthy proteins to fold in on themselves.