Quick--when I ask what an alien looks like, what's the first thing that pops into your head?

Is it a deadly endoparasatoid with two sets of sharp teeth?

Or perhaps a small, green, bipedal creature with large eyes?

Regardless of whatever you just pictured, you've seen these gray alien extraterrestrials somewhere before.

Called Zeta Reticulans, Roswell Greys, or simply Grays, these extraterrestrials are defined by their humanoid forms, exaggerated long limbs, large black eyes, small noses, thin mouths, and, of course, gray skin or gray clothing.

There are mostly two types of Grays-- the smaller drone or lackey type and the more powerful and intelligent Tall Grays.

Grays are some of pop culture's most recognizable representations of extraterrestrial life.

But where did this depiction of extraterrestrials come from, and why are Grays the ones mostly responsible for all the abductions?

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

Let's keep in mind that supernatural abductions have long had a place in folklore, mythology, and culture.

From religious rites to fairies, deities to aliens, history is filled with stories of humans being kidnapped, manipulated, and sometimes returned to their homes.

That's partially why it's hard to say when the first so-called alien encounter took place, though one of the first on record emerged in 1638.

The journals of Governor John Winthrop of the Massachusetts Bay Colony report the spottings of various slight apparitions in the area, some accompanied by disembodied voices.

This rash of sightings started a trend that has continued into the present day.

Most extraterrestrial encounters appear in the English-speaking world.

The 19th century is full of reports originating in the United States, like on January 22, 1878, when Texas farmer John Martin claimed he saw a flying disc that appeared to be the size of a saucer in the sky.

A local newspaper immortalized the story the next day.

At the end of the 19th century, residents across California reported incredibly fast-moving mystery airships about 45 to 60 meters in size.

Beginning in Sacramento in November, 1896, hundreds of witnesses reported lighted aircraft in the sky.

Many heard voices or singing emanating from the objects.

One witness described it as "cigar-shaped with wheels, piloted by two men."

Similar sightings moved eastward across 20 states over the following six months.

One witness claimed he narrowly avoided abduction while out driving his buggy some 80 kilometers north of Stockton, California.

He discovered what he de termined was a crashed ship-- a metallic, smooth object roughly 45 meters long.

Inside were three pale, thin, seven-feet-tall warbling creatures who tried to force him aboard, but he resisted and fled.

The shift from fairy abduction motifs and supernatural encounters to more technology-based extraterrestrial reports could be attributed to emerging technologies and a cultural movement away from superstition.

And let's not forget that the 19th century marked the first successful non-balloon-powered fl ight crafts in human history.

Gliders and controlled aircraft po wered by steam engines, compressed air mechanisms, and eventually battery-powered crafts were tested by governments, scientists, and hobbyists.

Many of these attempts were well-publicized.

Just saying.

Still, all was relatively quiet on the alien-encounter front until the 1940s.

1946 to 1960 brought another wave of sightings, this time across the Western world, earning the period the moniker "The Flying Saucer Era."

The United States, Germany, Norway, France, Italy, and Finland saw spikes in unusual aerial phenomenon.

Most reports indicated the appearance of either a cigar- or circular- sh aped wingless aerial craft accompanied by bright lights.

The press labeled these first European sightings a the "Ghost Rocket" scare of 1946.

The public and intelligence organizations alike nervously wondered if these flying objects weren't alien craft but real missiles originating from the Soviet Union.

Cold War anxieties have long been proposed by historians as one explanation for increases in sightings.

Other considerations?

The blossoming movie and television industry's embracing alien mythology and the growing popularity of the science-fiction genre across all forms of media.

1947 was quite the year for alien activity.

That year, U.S. pilot Kenneth Arnold observed nine objects he said moved like a saucer being thrown across water.

A newspaper reporter misunderstood and published Arnold's description as a "flying saucer."

As the news of the encounter and term spread, so many sightings were reported that the Air Force opened an investigation.

And July 8 is an infamous day in alien encounter history-- the Roswell Incident.

Following a press release from the official U.S. Army Air Force, the Associated Press reported to radio shows and newspapers that the remains of a flying disc had been found outside Roswell, New Mexico.

The U.S. military quickly retracted its initial report in a statement from the Roswell Army Air Field, claiming the object was a weather balloon.

As unidentified aerial phenomenon sightings increased in the '40s and '50s, so did the diversity and frequency of aliens in science-fiction texts.

The 1950 movie "The Flying Saucer" capitalized on the fascination with spacecraft.

Other movies like "The Day the Earth Stood Still" portray aliens as so humanoid they appear to be humans.

Their technology and status as extraterrestrials is what marks them as alien.

Technology in the real world was changing as well.

The first artificial Earth satellite launched on October 4, 1957.

That same year, the Gray alien legacy begins to appear in reports.

Brazilian farmer Antonio Vilas-Boas claimed he saw a red star that grew brighter as it approached him in the sky.

He testified that short beings from outer space wearing gray suits took him to the spacecraft and performed physical and sexual experiments on him.

Gray abductions did become a global sensation four years later in New Hampshire on September 19, 1961.

As Barney and Betty Hill were driving down a lone stretch of dark road on Highway 3 in the White Mountains, Betty noticed strange lights in the sky that she initially mistook for a falling star until it moved upward and increased in intensity.

The couple stopped the car to look at the lights and walk their dog.

While Barney was with the dog, Betty looked at the lights through binoculars, and what she saw shocked them both.

Betty would later describe a saucer-shaped craft with flashing multi-colored lights moving jerkily through the sky.

The duo jumped in their car ag ain to pursue the phenomenon.

It suddenly came closer-- much closer-- hovering over them in the middle of the highway.

Barney emerged, gun and binoculars in hand.

The pancake-like craft had a window, and Barney could see at least half a dozen figures inside.

They began to emerge.

Gray in color, human-like, but smaller in stature and with massive eyes, the creatures were accompanied by a buzzing sound.

Barney and Betty entered a trance state.

When they returned to consciousness, seated in the car two hours later, 56 kilometers away, neither could remember where they had been or what had happened.

They concluded they had been abducted by aliens.

Their experience became the first widely publicized alien abduction.

The next morning, a few unusual things seemed to confirm their suspicion.

Their watches were stopped; a pink, powdery substance stained Betty's dress; the binocular straps were broken; and circular indents adorned the trunk of their car.

Days later, Betty would report vivid dreams that filled in the details of their lost time.

In the dreams, the couple was taken aboard the craft, physically examined in detail, and questioned telepathically by the extraterrestrials.

It wasn't until three years later that they took their story public, first to a UFO study group, and then a month later, to seek the help of a hypnotherapist.

He concluded that their experience was a result of Betty sharing her dreams, not an actual alien abduction.

The Hills eventually reported the incident to the U.S. Air Force, who basically ignored it.

The National Investigations Co mmittee on Aerial Phenomenon, however, found the story plausible.

Following Vilas-Boas' and the Hills' reports, human extraterrestrial encounters took on a rather specific formula-- a person is taken, usually against their will, onto an alien craft where they experience a traumatic physical examination which includes the reproductive system in what would come to be known as "probing."

Sexual activity between humans and non-humans may occur.

The person is then returned with only a fragmented or partial memory of the events.

These experiences seemed ripped from pulp novels and movie screens of the time and gained more and more notoriety as they were told and retold in both fiction and nonfiction.

Today, may scholars have connected the Hills' abduction story and its popularity to racial anxiety.

Betty and Barney were an interracial couple and active members of the New Hampshire Civil Rights Movement, and by their own account, the aliens were fascinated by their differences in skin color.

Apparently, so was the American public.

John G. Fuller wrote a book about the Hill abduction in 1966.

"The Interrupted Journey" was commercially successful enough that it inspired a 1975 film adaptation, "The UFO Incident."

That same year in Arizona, Travis Walton reported an abduction incident almost exactly like the one experienced by the Hills just two weeks after "The UFO Incident" aired on television.

Hill would record his experience in the book, "Fire in the Sky," which also became a film.

Accounts of alien abductions spiked in conjunction with an increase in extraterrestrial encounters onscreen, continuing a cycle of fiction imitating life imitating fiction.

The appearance of Grays was solidified and popularized in 1977 with Steven Spielberg's "Close Encounters of the Third Kind" and again in 1988 with the cover art of Whitley Strieber's true-life alien encounters science-fiction book "Communion."

Almost 40 years later, in 1980, "The Roswell Incident" was published, reigniting the belief that the 1947 crash was evidence of aliens on Earth an d a government cover-up.

And in 1989, "Unsolved Mysteries" aired a so-called investigative report into the rumored extraterrestrial activity in Roswell to 28 million viewers.

The 1990s brought a veritable golden age of alien abductions in popular culture.

To better understand the community that has arisen around this subject of aliens, I asked for some help from "Subcultured's" Josef Lorenzo, who recently took a deep dive into the UFO enthusiast community.

I've been using the word "enthusiast" to describe the community because not everyone is a believer.

Some people that are in the community are skeptics; other people are believers.

And so I've been using the word "enthusiast" to kind of describe the community as a whole because they do come together-- they have this one common goal, and that goal is that they want more information.

There's a big pop-culture element of people's interest in UFOs and UAPs, and I think a lot of that goes to "The X-Files."

Like, "The X-Files" obviously was huge in the '90s.

Everyone was crushing over Scully and Mulder, and it was like this huge resurgence.

So there has been this, like, growing interest in aliens as an aesthetic.

But I do think that there is this reality that people are just also interested in aliens as, like, a real thing too, not just an aesthetic.

It's kind of like an underlying cause for that.

(Emily) The Hill abduction inspired an episode of "The X-Files" and NBC's "Dark Skies" series.

Carl Sagan even discussed it on his "Cosmos" show.

Books, including academic ones, abounded.

Reputable newspapers wrote st ories of reported abductions.

Tabloid front pages, TV shows, radio programs--everyone wanted in on the trend.

Hollywood blockbusters like "Independence Day," "Fire in the Sky," "Progeny," "Contact," "Mars Attacks," and "Men in Black" to name a few likewise profited off our alien obsession.

Since the mid-20th century, there have been four million reports of alien abductions in the U.S. alone.

The biggest thing that kind of happened for the community was that, in 2017, when that "New York Times" report came out admitting that the Pentagon had a secret program that has been looking into UAPs.

The one thing that I think is really significant about this last, like, 20 years is that if you-- Gallup did a poll in 2005.

They found that 24% of people in the United States believe that extraterrestrials have visited Earth.

And when Gallup did the same poll in 2021, they asked people if these UFOs-- this footage that has been released by the Pentagon is evidence of intelligent life outside of Earth, 51% of people said that they believed it was.

This staggering number could be explained by the desire for money or fame.

Some people have used abduction as a justification for sudden absences at home, covering for an extramarital affair or a particularly raucous night out.

Psychologists have debated in the influence of false memories-- a scientifically proven occurrence where memories of incidents that never occurred are implanted into consciousness with suggestive questioning and distortion of real-world events.

Sleep paralysis is another proposed explanation.

Many people report that their abductions occurred at night in their bedrooms where the person is startled awake to find the aliens at their bedside.

Sleep paralysis is often accompanied by auditory or visual hallucinations as well as temporary body paralysis.

Then there are comets and asteroids to consider, as well as atmospheric phenomenon like ball lightning or St. Elmo's Fire.

Hoaxes could be another cause.

But still, many people swear that real contact between humans and extraterrestrials has occurred.

This might sound silly, but I like to say that the level that you believe is also a spectrum.

You know, we talk about gender and sexuality being a spectrum, but there is a huge spectrum of people who believe things-- the aliens are already here; they are reptilians; they have all these different depictions.

And that goes to just like, okay, UFOs have been here before and those are extraterrestrials.

No indisputable evidence has ever been produced from an alien abduction-- no objects, hybrid offspring, devices, or even photographic evidence.

But that doesn't mean people have stopped believing in extraterrestrial life.

Quite the opposite.

Then that goes to, "These are UFOs.

Maybe they're extraterrestrials?"

And it goes to skeptics that are like, "No, this is all a sham," or "This is all just the government" or whatever.

So there's this big spectrum of people that are in this community that all believe different things.

And it creates a lot of division, a lot of drama.

People get really, really emotional about where they stand and where other people stand.

We've seen more varied interpretations of extraterrestrial life in the 21st century.

As our knowledge grows, we've expanded the concept of extraterrestrial life past green Martians and Grays to sentient beings that come to Earth to share their knowledge.

As science and technology advances and our understanding of the universe expands, our conception of what constitutes life does as well.

Science fiction helps us imagine the philosophical, practical, and moral implications of real encounters between aliens and humans-- an intellectual testing ground cloaked in the trappings of fantasy to make it more digestible.

And in exploring these hypothetical scenarios, we question what it means to be human.

In other words, how we conceptualize aliens in science fiction is often more about us than it is about them.