One of the strangest questions left by Na Hong-jin’s HOPE is something many viewers may not immediately consider:
Are the monsters and the aliens actually the same creatures?
At first, the answer seems obvious.
Something extraterrestrial arrives.
Terrifying creatures appear.
Humans are attacked.
So naturally, viewers connect everything together.
But after looking more closely at what happens in the film, an interesting theory emerges:
The monster-like creatures and the more humanoid aliens may not be exactly the same beings.
Viewers discussing HOPE online have pointed to differences in appearance, behavior, physical durability and the way the creatures respond to injury.
If those differences are intentional, then one of the biggest assumptions we make while watching HOPE could be wrong.
Perhaps there is not just one alien species in the story.
Why Do We Automatically Assume They Are the Same?
The movie gives viewers very little time to understand what has arrived.
The human characters are frightened and confused.
So are we.
When strange creatures begin appearing after an extraterrestrial event, the simplest conclusion is:
They are all aliens.
That is exactly how people would probably react in real life.
Nobody stops during an emergency to construct a detailed extraterrestrial taxonomy.
But HOPE is a movie built around uncertainty and perception.
What characters believe they are seeing is not necessarily the complete truth.
That makes the differences between the creatures worth examining.
The First Major Clue: They Do Not Seem Equally Vulnerable
One of the strongest arguments behind the theory is physical durability.
Some creatures appear capable of being injured.
They bleed.
They suffer visible physical damage.
And at least some encounters give the impression that sufficient violence can stop them.
But the more humanoid alien beings appear extraordinarily difficult to kill.
Gunfire and other forms of extreme violence do not always produce the results humans expect.
That creates an obvious question:
Why would members of the same species react so differently to physical damage?
There could be several explanations.
They may be different species.
They may be different forms of the same species.
They may have different biological functions.
Or the apparent difference may simply reflect circumstances the audience does not yet understand.
But the contrast is significant enough to deserve attention.
Theory #1: The Monsters Are a Completely Different Species
The simplest version of the theory is that there are at least two extraterrestrial species in HOPE.
The humanoid aliens are one.
The monster-like creatures are another.
If that is true, their arrival may involve an ecosystem rather than a single species.
Think about human exploration.
Humans do not travel alone.
We bring animals, microorganisms, technology, food and countless other biological materials with us.
An advanced alien civilization could do something similar.
The monsters might therefore be creatures transported by the humanoid aliens.
They could be companions.
Livestock.
Predators.
Biological tools.
Or organisms that escaped after something went wrong.
This would explain why the two types of beings appear connected to the same event without necessarily being identical.
Theory #2: The Monsters Could Be Alien Animals
This may be an even more interesting possibility.
What if viewers are making the same mistake the humans make inside the movie?
We see something frightening and intelligent-looking enough to threaten us, so we call it an “alien.”
But extraterrestrial life would presumably contain the same kind of biological diversity found on Earth.
Humans and wolves are both Earth life.
That does not make wolves human.
Humans and insects come from the same planet.
That does not make them the same species.
So why should every creature arriving from another world be considered the same alien?
The monster-like beings could simply be the equivalent of alien animals.
That would also help explain differences in behavior.
A humanoid alien may have complex goals.
A creature accompanying it may act largely through instinct.
Humans encountering both during a crisis would have no way of knowing the difference.
Theory #3: They Could Be Different Forms of the Same Species
There is another possibility.
Perhaps they are biologically related after all.
But they represent different stages or forms.
Earth already contains animals whose bodies change dramatically throughout their life cycles.
A caterpillar and a butterfly look so different that someone unfamiliar with their biology might assume they were unrelated creatures.
Alien biology could be far more extreme.
The monsters might represent an earlier developmental stage.
The humanoid aliens might represent a mature form.
Or environmental conditions could trigger physical transformation.
If that is the case, differences in durability could also be explained by development.
One stage may be vulnerable.
Another may possess extraordinary regenerative abilities.
This remains speculative, but HOPE gives viewers enough biological mystery to keep the possibility open.
Theory #4: The Monsters Could Be Engineered Organisms
There is also a darker interpretation.
The monsters may not be naturally occurring animals at all.
They could have been created.
An advanced extraterrestrial civilization might use biological organisms the way humans use machines.
Instead of building a robot to explore a dangerous environment, perhaps they grow a creature designed for the task.
Such organisms could be used for reconnaissance.
Protection.
Hunting.
Environmental adaptation.
Or warfare.
If the humanoid aliens created the monsters, then the physical differences between them would make perfect sense.
They were never supposed to be biologically identical.
But this theory creates another major question:
What were the monsters designed to do?
If they were designed for violence, the aliens become more threatening.
If they were designed for survival or exploration, humans may once again be misreading their purpose.
Their Behavior May Be Just as Important as Their Bodies
Physical appearance is only part of the mystery.
Behavior matters too.
The more humanoid aliens appear to have motives that extend beyond immediate violence.
The ending especially suggests that at least one alien has a specific personal objective connected to a child.
That implies memory.
Relationships.
Purpose.
Possibly even family structure.
The monsters do not necessarily display those same motivations.
They appear much more creature-like.
That behavioral difference could be intentional.
If one group operates through complex goals while another behaves more like an animal, the movie may be showing us two fundamentally different forms of extraterrestrial life.
Why the Forest Matters
Some viewer theories have also focused on the number and distribution of the creatures.
The presence of multiple monster-like beings raises another question.
If there were only one alien visitor, why are there apparently multiple creatures?
Did they arrive together?
Were they released?
Did they reproduce?
Were they already inside whatever arrived from space?
Or did something transform after reaching Earth?
The film does not provide a simple answer.
But multiple creatures make the “alien animal” or “different species” theory more interesting.
We may not be watching one extraterrestrial visitor.
We may be watching the beginning of an entire alien biological event.
The Giant Ship Could Be Connected
The mysterious spacecraft imagery near the end may also matter.
If the larger ship contains more than individual humanoid aliens, then the scale of the story changes dramatically.
A ship capable of interstellar travel could contain an entire controlled environment.
Multiple organisms.
Different species.
Different biological roles.
Perhaps even different civilizations.
That would make the creatures encountered by humans only a tiny sample of what exists beyond Earth.
The first HOPE film may intentionally show us almost nothing about the larger alien world.
What looks like a complete invasion story could actually be first contact with a much larger ecosystem.
But There Is a Problem With the Different-Species Theory
We should not treat this theory as confirmed.
There are other explanations for the differences viewers notice.
The creatures may simply have different levels of injury.
Different ages.
Different physical states.
Different roles.
Or the film may use visual differences without intending to establish separate species.
There is also the possibility that humans—and therefore viewers—do not understand what we are seeing well enough to classify anything accurately.
That uncertainty is important.
The evidence supports asking the question.
It does not yet support declaring the answer.
Could the Monsters Be Transformed Humans?
There is an even darker possibility worth considering.
What if at least some of the monsters did not arrive in that form?
Could contact with alien biology transform another organism?
Could infection, reproduction or biological assimilation create the monster-like creatures?
If humans or Earth animals can be changed through contact with extraterrestrial material, the monsters could represent the result of that process.
This would explain why their biology differs from the humanoid aliens.
It would also make the extraterrestrial threat far more complicated.
The danger would not simply be an alien attacking humans.
The danger could be alien biology spreading through Earth’s ecosystem.
There is not enough evidence to call this the leading explanation.
But it is exactly the kind of question a sequel could explore.
The Heart Mystery Could Help Solve This
The alien heart may eventually provide the answer.
If the humanoid aliens possess a unique biological system centered around the heart, then examining whether the monsters share that system would immediately tell us whether they are closely related.
Do the monsters regenerate in the same way?
Do they possess the same critical organ?
Can they survive similar injuries?
Can their bodies be restored?
If the answer is no, the different-species theory becomes much stronger.
This is why the heart mystery and the creature mystery may ultimately be part of the same puzzle.
What If Humans Are Fighting the Wrong Enemy?
This is where the theory becomes especially important to the story.
Suppose the humanoid aliens and monsters are different creatures.
Then humans may have made a catastrophic mistake.
They may encounter dangerous monsters and assume:
The aliens sent them to attack us.
But what if the humanoid aliens are also threatened by those creatures?
What if the monsters escaped?
What if something went wrong during their arrival?
What if the aliens are trying to recover, contain or escape them?
Suddenly the entire conflict changes.
Humans and humanoid aliens might not be natural enemies at all.
They could be facing the same threat without realizing it.
That Would Fit HOPE’s Central Theme Perfectly
HOPE repeatedly challenges perception.
Humans encounter something unfamiliar.
They interpret it through fear.
Then they act before they fully understand it.
The audience does the same thing.
We see monsters.
We see aliens.
We place them into one category.
Enemy.
But what if the movie is deliberately encouraging that mistake?
If a later revelation shows that the monsters and humanoid aliens were never the same thing, viewers would be forced to reconsider earlier events.
Who attacked whom?
Who was defending themselves?
Who was searching for someone?
And who was simply trying to survive?
That kind of reversal would fit Na Hong-jin’s approach far better than a simple “aliens invade Earth” explanation.
The Child Mystery Also Changes
This theory could even affect the child at the end.
If the alien is searching for his son or another child closely connected to him, what happened to that child?
Was the child harmed by humans?
Was he injured in the crash?
Or was he attacked by one of the monster-like creatures?
If the monsters are a separate species, then the alien’s search for the child could have nothing to do with conquering humanity.
He may be moving through a disaster trying to recover his family.
That would make the human-alien conflict even more tragic.
Both sides may be responding to dangers they do not understand.
So Are the Monsters and Aliens Different Creatures?
The most accurate answer right now is:
Possibly—but HOPE has not confirmed it.
There are enough differences to make the theory worth taking seriously.
The monster-like creatures appear different physically.
Their vulnerability may be different.
Their behavior may be different.
And the humanoid aliens appear capable of motives and relationships that the monsters do not obviously share.
But several explanations remain possible.
They could be separate species.
They could be alien animals.
They could be engineered organisms.
They could represent different stages of the same species.
Or viewers may simply be missing information that makes the differences easier to explain.
Final Thoughts
The most interesting thing about this theory is not simply whether the creatures have different biology.
It is what that difference would mean for the entire story.
If the monsters and humanoid aliens are separate beings, then HOPE may have deliberately encouraged both its characters and its audience to make the same mistake:
We saw something frightening, and we assumed everything unfamiliar belonged to the enemy.
That assumption may be exactly what turns first contact into catastrophe.
And if a sequel eventually reveals that humans were fighting one group while misunderstanding another, the biggest twist in HOPE may not be where the aliens came from.
It may be that we never understood who the real enemy was in the first place.
The theory that HOPE’s monsters and humanoid aliens may be different creatures raises another question: where does Kali fit into this mysterious alien world? Understanding the child could offer additional clues about the visitors and their biology. Explore who Kali is in HOPE and why the alien child matters for another perspective on the film’s unanswered mysteries.