(zombie growling) - We've made it to the 21st century in zombie history.

In my opinion, while the last 20 years have produced some of the most innovative and prolific zombie tales, it's been a complicated couple of decades, in part because there's already hundreds of years of zombie lore to work with, from the legacy of slavery displayed in the Haitian zombi in early Hollywood films to the flesh-eating Romero ghoul in popular culture.

There are a few societal changes that made things different in how these two legacies are carried on.

Terrorism on American soil, several concurrent wars, the recognizable impacts of global warming, genetic engineering, and sudden viral outbreak.

With these events came a new set of anxieties, which emerge in zombie narratives.

Zombies never died.

They can't after all, but they certainly have enjoyed a rebirth this century.

(dramatic instrumental music) I'm Dr. Emily Zarka, and this is "Monstrum."

(window crashing) (zombie screaming) It's challenging to simply define the modern zombie because there are so many different versions.

And it seems like the formerly fundamental element of zombieism is no longer essential.

They don't have to be undead, strictly speaking.

And even if they are, in some narratives they can be cured or at least controlled.

The 21st century zombie could be described as any humanoid being, living or undead, that craves human flesh and cannot fully control its basic instinct to consume.

But in many ways, it's an exercise in contradictions.

While generally mindless, we've also seen zombies who problem-solve.

While most are violent, in some cases even born of violence, (police officer screaming) some are likable.

- 'Sup?

- They can be slow-moving and decaying, incredibly fast and swarming, or anything in between.

When, and maybe more importantly why, did the zombie get so much range?

To answer that we need to figure out how zombies came to dominate the popular imagination.

Let's start at the end of the last century when some real-world events put terrorism and bio-engineered disease at the forefront of our minds, and when video games addressed these realities in their zombie characters.

(man screaming) In 1996, the zombie apocalypse survival game "Resident Evil" was released by a Japanese video game company to unprecedented critical and financial success.

The game has ill-intentioned chemists and geneticists working in secret developing bio-weapons that are released into the world and turn humans into zombies.

(gun banging) Likely inspired by earlier video games like "Sweet Home," (upbeat instrumental music) "Resident Evil" gave a name to a developing genre: survival horror.

The news zombie genre's popularity and the release of these games came on the heels of terrorists in Japan releasing deadly chemicals and toxins into unsuspecting cities.

1996 was also the year the arcade shooter game "The House of the Dead" was released, which featured, wait for it, zombies spawned by irresponsible and unethical scientists.

Both "Resident Evil" and "The House of the Dead" introduced a new trait: their zombies moved fast.

With these incredibly popular zombie-battling video games, the undead were officially entrenched in the public eye.

In fact, even the great zombie filmmaker George Romero gives credit in this way.

And a 2013 interview he said, "I do think the popularity of the creature "has come from video games, not film."

So in the late '90s, we saw this conflation of bio-engineering and zombification played out in the popular video games of the day.

And Japan wasn't the only country showing increased fear of bio-weapons.

The 1996 pipe bomb attack at Centennial Olympic Park in Atlanta, Georgia marked the first time bomb fragments were immediately sent to the CDC for chemical and biochemical testing.

No toxic agents were found, but the event marked a point when bio-weapons became a real threat in American thinking, both politically and publicly.

Chemical and biological weapons of mass destruction became more prolific at the end of the 1990s.

Academic publications and news outlets reported that recipes for bio-agents like botulism toxin could be found on the internet and made at home.

Weaponizing a lethal sickness became a new reality, but it was the rise of natural pandemics such as SARS in 2003 and the H1N1 influenza pandemic in 2009 that revealed how quickly and easily a disease could spread throughout the world.

The subsequent rise in global popularity of the zombie movie, particularly in the first decade of the 21st century, offered a recognizable figure upon which to impose this anxiety: the pandemic zombie.

The pandemic zombie is categorized by the use of a pathogen that causes a disease that mutates the living human into someone we might not recognize as human.

It's a sick body no longer in control of itself and which poses a threat of spreading its contagion to others.

The first pandemic zombie film to hit big screens premiered in March of 2002, "Resident Evil," a spinoff of the video game series of the same name.

In this zombie narrative, the deadly corporate-made tyrant virus, or T-virus, designed under the guise of genetic research is released into the population.

Its victims reanimate from death with serious brain damage, causing them to attack swiftly and violently infecting others through bodily fluids.

Despite the existence of an antidote, as the franchise revealed in the following five films, the pandemic could not be stopped.

"Resident Evil" grossed more than $100 million worldwide.

In "28 Days Later," which was released the same year, the rage virus in all its bloody glory solidified a whole new generation of monsters, the fast-moving, decay-free zombie.

- "28 Days Later" zombies were earth-shattering for me.

The idea of runners, that was just something we had never seen before.

Earth-shattering.

- In fact, some people argue that you can't call the monsters in this film true zombies because the diseased humans who hunger for flesh and violence and suffer some loss of brain function are not technically reanimated dead bodies, and therefore are not really zombies.

But I disagree.

The mindlessness and lack of control seen in these diseased characters, and often the loss of personality and individuality suggest a loss of humanity, a defining characteristic of the original zombies.

- Even if you take, like, the lease zombie-like zombie, like "28 Days Later" where it doesn't even raise from the dead, it's just a viral infection, but people saw that movie and they went, "No, that's a zombie."

And I think the reason for that is if it's a body that is no longer in control of itself, it's just acting on autopilot and drive, and very often that drive is to consume, then that's zombie.

But the other part of it is that you have the mob which is such a trope.

I mean, it's very, very rare to get a lone zombie film.

- [Emily] Violence itself actually created the infected hordes in "28 Days Later."

The rage virus is a bloodborne disease that resulted from scientists attempts to cure anger in humans by conducting primate research with genetically-engineered Ebola virus.

- The chimps are infected.

- Infected with what?

- Rage.

- When an eco-terrorist group releases the laboratory's chimpanzees, the chimps go berserk, biting and infecting every human in the lab who in turn spread this rage virus around Great Britain.

The movie's eerie scenes of an abandoned London with newspapers bearing alarming headlines strewn throughout the street and countless missing posters on the sides of buildings uncannily call to mind similar images of the real New York City in the days following the collapse of the Twin Towers after the terrorist attacks of 9/11.

It can be argued that these scenes released so soon after the devastating experience served as both a reminder of the tragedy and as a catharsis for the audience.

The zombies in this film might as well be already dead, so killing them as a way for audiences to project their own need for justice onto non-human bodies.

For the next decade, the majority of mainstream zombie films follow the same basic premise as these two films, demonizing scientific intervention as the harbinger of the apocalypse, usually aided by corporate greed or terrorist activity.

"28 Weeks Later," "REC," it's American remake "Quarantine," and "Dead Girl," to name only a few of many early zombie narratives from the 21st century, all contain some element of scientific misjudgment as the cause of the zombie plague.

In the first decade of the 21st century, scientific intervention had become synonymous with death.

(woman screaming) The first Zombie Walk, where people dress up as zombies and other related characters to parade down city streets, occurred in Toronto in 2003.

That same year, Max Brooks published his satire on survival handbooks, "The Zombie Survival Guide."

Thinking about what you would do to survive the impending zombie apocalypse was nothing new for horror fans, but the mass-produced book flew off shelves, introducing different audiences to the undead, alongside some really practical survival tips.

- There's a lot that we can learn from horror, but it's definitely a good idea to a zombie bag somewhere because I think a lot of us have figured out that we do, to a degree, all of us have to be survivalists in the sense that we have to be ready in case, and when, and by the way things are going wrong.

(laughs) - [Emily] "Shaun of the Dead," featuring Romero-style zombies in a dark comedy makes the slow-moving, flesh-eating undead funny, offsetting blood with humor.

- No, that's rubbish.

- [Emily] "Zombieland" and "Warm Bodies" would later follow suit with laughs and some pretty brutal gore.

It's kind of crazy that we've gone from zombies that represent slavery to zombies that are funny.

- They still out there?

(zombies moaning) - Yeah.

- And I can't do a modern zombie episode without talking about "The Walking Dead."

But I can't really say if they're pandemic zombies or not.

First release in 2004, the ongoing zombie series features a more classic homage to the Romero zombie.

It's even in black and white like the original "Night of the Living Dead."

The comic's success led to "The Walking Dead" TV show, which itself inspired two spinoffs, and apparently three forthcoming movies.

Then there was the amazing video game in 2012.

"The Walking Dead" even has its own freaking Monopoly edition.

That's when you know something has become a cultural icon.

I could argue that in the last 10 years, there's been a shift in how science is portrayed in a lot of recent narratives.

Regardless of the classification of zombie, survivors turn to science more as a means of salvation rather than destruction.

"Maggie," "What We Become," and "Pride and Prejudice and Zombies" suggest the zombie virus evolved naturally.

Even the film adaptation of "World War Z" attributes the zombie plague to nature with one character, a virologist, stating- - Mother Nature is a serial killer.

- Other zombie films attribute their flesh-eating monsters to an intentionally spread sexually-transmitted infection, an evil cell signal, and a minor leak from a biotech district.

What all of these films show is that we now fear humanity, or nature's response to it, more than we fear science.

We no longer see science as a weapon, but as our only hope for survival against an increasingly multiplying threat.

And I mean that quite literally.

Another trend in many of the most recent pandemic zombie narratives is the sheer volume of zombies plaguing humanity.

The utterly chaotic scenes in "World War Z" legitimately give me anxiety.

While the zombies in Brooks' original book were slow-moving, reminiscent of Romero zombies, Hollywood's version took them in a totally different direction.

They are very, very fast and strong.

And it's not a hundred or even a few thousands zombies, but literally hundreds of thousands, even millions onscreen.

I call this type of zombie the hive zombie after the insect species these animalistic, swarming hoards mimic.

These zombie surge across cities in minutes, overwhelm transportation in seconds, and mow down any obstacle in their way by sheer number.

This zombie is terrifying because it cannot be stopped with brute force or isolation.

The sheer number of people who are infected or could be infected overwhelms any existing institutional structures.

Then COVID-19 happened.

And while it hasn't turned us into zombies yet, the formerly fictional idea of a highly contagious pandemic for which we were woefully unprepared became a very harsh reality.

What do you think zombies gonna look like next, especially with COVID-19?

And do you think we're going to see that translated into horror movies, specifically zombie horror movies?

- Well, I've been waiting forever for zombies to learn how to shoot guns because with all of the mass shootings, I thought, okay, that's gotta be the next thing.

And I mean, there's some films like "Crazies" that are zombic, like zombie-like, and there's "Land of the Dead" where zombies learn how to use tools.

The pandemic is us test driving the ecological catastrophe to come.

So, I'm really expecting the eco zombie, as I call it, to be a very big phenomenon.

- I think now zombie storytelling is probably going to lean more into what those subtexts are.

What zombies mean in terms of relationships, what zombies mean in terms of community, what zombies mean in terms of these fears, these societal fears of change we're talking about.

I think those are the zombie projects in the future that will thrive.

- [Emily] Many of us are witnessing or even experiencing firsthand the effects of a global viral pandemic, thereby importing a sense of poignancy to what was once a fun distraction.

- Horror is our socio-cultural syllabus.

It reveals our foibles, it comments on our both social and political world, and it does it bravely and boldly because in a lot of ways we're not expecting horror to be, you know, "Saving Private Ryan" or "Sophie's Choice."

They're using their narratives to be brave and to be bold.

And in some ways, that's really liberating.

- [Emily] In 2018, Jordan Peele became the first Black winner for best original screenplay for his horror film "Get Out" proving what many horror fans already knew, that there is power in telling these stories.

I think it's possible to even read the movie as a zombie metaphor.

- Creative people can create metaphors out of anything, but the zombie is uniquely malleable.

It just lends itself to communicating a message beyond the apparent surface message of the story.

Change always comes from the fringes, and horror is the quintessential fringe genre.

- The great thing about horror is, you know, traditionally this was a place where people would start in filmmaking because you didn't need a lot of money.

They just had an idea and they had their fears and they found a way to bring them to the screen.

- Zombies are unique in the world of monsters because they are us.

While science says that life ends with death, human mythology has always grappled with this across history and cultures.

We are fascinated, even obsessed, with the idea that we could succumb to a worst fate, zombification.

Anyone can become a zombie so we see ourselves, our loved ones, our entire communities reflected in the images of those walking corpses.

Because death is the greatest unknown and our deepest fear, we inherently dread what comes next.

And it is perhaps an innate horror, this idea that after death we might not be able to rest in body or spirit.

The undead aren't scary because they are deceased, but because they are restless, ceaseless and insatiable.

It's like our own bodies, our own loved ones can return to harm us, meaning no one is safe.