(host) First impression of the now-classic "Cujo"-- a mother's fight to save her son's life while being terrorized by a rabid dog blocking her escape.

Second impression: "Cujo" is a modern-day hellhound, guarding the threshold between the dead inside the house and the mom clinging to her son's life outside.

Hellhounds are mostly black-furred and startling, with red, glowing eyes, employed by a leader of the afterlife.

Take the terror dogs from "Ghostbusters," servants of Gozer, the all-powerful entity from another dimension who ruled over a dark, underground realm of souls.

Vinz Clortho, the Keymaster, and Zuul, the Gatekeeper, take the form of horned, red-eyed hellhounds on Earth.

Tasked with guarding the entrance to a literal hell gate to Gozer's realm, they are an iconic anomaly in modern popular culture for their unusual ability to possess humans.

Even hardcore dog lovers would be hard-pressed to call these canines "cuties."

The hounds of hell may not try to sink their fangs into your flesh or tear you limb from limb-- every time-- but your eternal life is entirely up for grabs.

So, are dogs man's best friend or underworld enforcers?

I'm Dr. Emily Zarka, and this is "Monstrum."

I'm using "hellhound" here as an overarching term to refer to preternatural canine creatures who are associated with the afterlife or underworld.

Many dogs in early folklore and mythology are connected to these places, but that isn't to say that they were all inherently evil.

In some ways, early death dogs were guides and protectors.

Take Anubis, the jackal or jackal-headed Egyptian god of the dead and mummification, who protected the resting place of the physical body and guided the soul to the afterlife.

Similarly, Shyama and Sabala were Hindi hounds who guarded the gods of death's gates, each with two sets of eyes-- the better to protect you.

Cerberus, the three-headed hound who guards Hades, keeps the souls sequestered there and keeps the heroes out.

He can be a good boy, though.

I mean, he adorably falls into a slumber if you play him a little music, which you might want to do, since otherwise, he could just eat you.

In Mesoamerican spiritual beliefs, in some Latin American traditions, dogs guide the souls of the dead to the next world.

And if you mistreated a dog in life, in death your soul was at risk to wander for eternity.

In various Middle Eastern and Indian traditions, dogs were the escorts into the afterlife, brought into the room of a dying person to shepherd their passing.

But these hounds aren't inherently evil or scary.

Why is it all hound and no hell?

Funny you should ask.

In Nordic sagas, there's Garmr, a bloodstained hellhound.

His mistress was the death goddess Hel, who presided over the underworld, and his howl is said to signal the beginning of Ragnarök.

We also start to see the line between guardian and menace blur as BCE turns to CE.

Influential Roman poet Horace wrote of a "dark companion," a "black dog" who symbolizes misfortune and despair.

Greek philosopher and historian Plutarch went so far as to call dogs "impure" because of their association with the goddess Hecate, who sacrificed dogs to serve as guides for souls in the afterlife.

The goddess herself was even referred to as a "black female dog."

Mosaics in Ancient Greece show ferocious black dogs guarding the entrance to homes-- the earliest precursors to "Beware of Dogs" signs.

In the first and second century CE, dogs were incorporated into folklore as harbingers of misfortune, which, given their close relationship with humans and the potential to be aggressive, made them easy targets.

With the rise of the Medieval period, as we begin to separate the animal from Homo sapiens, dogs continue to be demonized, but also commonly prized as loyal companions and working animals.

In Medieval Middle Eastern culture, dogs were considered dirty, disease-ridden creatures, and all roots for the word "dog" have negative connotations, like "rabid" or "crazed."

Nevertheless, like the earlier social and spiritual roles of canines across the world, they could also be guard dogs or domestic helpers.

The liminality of the dog as inside/outside, helper/harmer in equal measure, parallels the boundary between life and death.

Much like life and death, we both fear and revere canines.

So, a supernatural version of an everyday animal spanning that threshold kind of makes sense.

Darkness is associated with obscurity, representing more negative connotations than positive ones, and why many of these hellhounds were described and depicted with black fur.

In Medieval Europe, black canines appear in medical texts, associated with melancholia and other illnesses.

In one 1800s CE French text, it is written that one could determine if a person was terminally ill by taking a tick from a black dog and holding it in the left hand.

If one presented to a gravely ill person, they turn toward it-- they're a goner.

Black dogs continued to be associated with illness centuries later.

Even in the late 18th century, the black dog is linked to depression.

This terminology lingered into the 19th and 20th centuries, where bad moods were attributed to having a "black dog" on one's back or worrying you at home.

Winston Churchill would reportedly refer to his own struggles with depression as his "black dog."

Here on "Monstrum," we know that Christianity loved to adopt and distort older spiritual beliefs and folkloric traditions, especially to support its agenda.

So it's not all that surprising the devil entered the equation, taking the hellhounds of folkloric traditions and pre-Abrahamic spiritual practices into the devil and witchcraft game.

Animals often serve to normalize the supernatural by marrying it to something non-human but still in the realm of tangible familiarity.

Connecting demonic possession with an animal represented the beastly or primal desire of the human animal.

And, as we know, primal desires are a no-no for the church.

In the 1574 demonic possession case of English lawyer Robert Briggs, a demonic dog plays a central figure.

Described as horrifically ugly, with a shaggy, blackish-red coat, the dog would reportedly follow Briggs around London.

Briggs himself was terrified of the monster, and at one point, even jumped into the Thames to shake the creature.

The dog was said to be an earthly manifestation of the devil himself.

Other possession accounts from the 16th century include symptoms such as sounding like a hellhound, acting like a wild dog, or communicating with dogs.

In a case at the turn of the century, the devil communed with his victim, William Sommers, in the form of a talking black dog.

Hellhounds seem to be primarily associated with transient spaces, whether those are spaces of physical travel and movement, like roadways and gates, or places of metaphysical transformation-- graveyards or execution sites, for instance.

English folk culture is perhaps where this trend is most obvious, but it's by no means exclusive.

Great Britain, Ireland, France, Scandinavia, Germany-- all of these place tell tales of the black dog-- a special variation of the hellhound trope distinguished by its massive red eyes and long, thick, black coat whose presence always foretells death and disaster for those who see it.

Wandering spirits and lost souls are often said to take the form of spectral dogs.

In German lore, they appear as shaggy dogs with black fur and unnaturally glowing eyes.

Although, in a unique quirk, if any specific breed is noted in the description of these German creatures, it's often the poodle.

Seems a bit odd, unless you know that the poodle traces its heritage back to Germany where they were bred as duck-hunters.

Ghost dogs with black coats and red eyes are reported all across England, sometime under the name "black shuck"-- a regional variation of the black-dog motif specific to the eastern countryside of England.

The monster is said to be a demonic being, either a hound from hell, a demon familiar, or both.

It may be accompanied by a foul smell.

Shuck comes from "Shucky," a local term for hairy or shaggy, or the Old English word for "demon."

Some scholars connect the black shuck and other demonic dogs in England to the legend of the wild hunt-- a spectral hunting party that seeks the souls of the living, the first written account of which appears in 1127.

The first written recording of the black shuck, however, appears in 1577.

According to this early legend, during mass at an Anglican church in Blythburgh, a clap of thunder rang out before the doors to the church slammed open, revealing a giant black dog who tore through the building, killing two people before causing the steeple to collapse.

That same day, another church in Bungay experienced a black shuck visit as well.

The same dog stormed into the building accompanied by lightning, clamping onto the necks of two congregants, killing them.

The floors of both churches bore scorch marks where the dog's paws had touched-- ones that some swear can still be seen today.

Unsurprisingly, the dog was associated with the Devil.

The prevalence of black dogs in British folklore, literature, and oral tradition from the 17th century onward is responsible for dominating popular culture's understanding of spectral hounds.

Take the 18th century case of the old woman and the chimneysweep from Hertfordshire, England.

As the story goes, an old woman was drowned for her suspected use of witchcraft-- a murderous deed carried out by a chimneysweeper who himself was publicly hanged near the spot.

After this second death, a black dog appeared in the area.

As big as a Newfoundland but malnourished, the shaggy, black-haired creature's long teeth protruded from his grinning mouth, his eyes glowing like balls of fire.

Despite his frightening appearance, the creature never did more than suddenly appear, giving unsuspecting travelers a fright.

In Lincolnshire, a taller and thinner version of the black dog appears near a deep pond surrounded by trees.

Water has long been associated with liminality.

Ponds, rivers, wells, and even puddles could be portals to the otherworld, and the dangerous nature of all bodies of water links them to death.

Some rationalize sightings of these monsters as culturally based fear responses to stressful events-- eerie nighttime encounters, death, or destructive thunderstorms.

Others say the sightings can be attributed to panthers or large cats that escape from private residences and zoos.

Some insist the sulfur smell that may accompany the black dog is not the sign of a hellish origin, but the result of hydrogen sulfide gas produced by the rotting vegetation of the wetlands, where many of the sightings took place.

The boom of published folklore collections in the 19th century also meant hellhounds began to pop up again in fictional literature.

Famous Victorian texts like "Jane Eyre," "The Hound of Baskervilles," and "Dracula" solidified the presence of monster dogs in 19th century Gothic literature.

In more modern literature and film, the idea of hellhounds and spectral dogs of all sorts has become more varied.

They've played tribute to ancient Greek mythology and continue to serve as metaphors of ill omen, but they've also appeared as happy ghost hounds and lovable spirit guides.

These varied and various representations display our changing view of canines and, arguably, our renewed appreciation for older traditions.

So, despite modern society's infatuation with puppers, doggos, and booping the snout of fluffers, we can't seem to fully remove the dog from the hellhound.