There are tons of monster movies that have a nasty creature doing whatever it can to destroy any human they come upon, but not all movies like that are as straightforward as they appear. In a lot of these films, the real monster isn't the one tearing apart some space station crew; it's the people themselves. The "humans are the real monsters" trope is somewhat subtle in a lot of movies, and not every example is as easy to detect as one might think.
One of the movies that comes close is Godzilla. Sure, the monster is destroying Tokyo, but the message of the film is all about mankind's disregard for nature and love of atomic weapons results in the creation of a monster that destroys them. That's a close one, but at the end of the film, it's still a giant monster crushing Tokyo.
The movies on this list are the ones that take it a step further. Either the humans did something stupid, or they went out of their way to mess with an alien species, and they wind up paying for it in the end. Check out the movies listed below, and if you see ones you think fits the trope more than the rest, be sure to give it a vote up to see which one rises to the top!
In the world of District 9, a spacecraft filled with alien refugees arrived on Earth over the South African city of Johannesburg. Over time, the aliens were allowed to resettle on Earth beneath their hovering craft, but they were heavily policed and regulated by the human police and military of the city.
The largely sick and malnourished aliens are placed into a resettlement camp called District 9, and they live in squalor. As the events of the film take place, the local authorities are beginning the process to resettle the aliens into a new area. The film's premise was inspired by the very real, yet alien-free events in Cape Town's District Six, which was the location of a forced resettlement during the Apartheid era.
It's clear in this movie that the humans are the true monsters, and there's little denying it. They are brutal in their treatment of the aliens and show true xenophobia and social segregation where the refugees are concerned.
James Cameron's Avatar was a futuristic depiction of the brutality of humans on native people, and if you caught the parallels of that theme to the European conquest of the New World, you must have been paying attention.
The movie follows Jake, a paraplegic veteran who is taken to a planet so he could fill a role only he could, as his DNA matched his twin brothers, who had recently passed away. He was needed to control his brother's avatar, which was essentially a bio-engineered native without a mind of its own.
He gets into his new skin, explores the world a bit, and falls in love with a native, eventually earning the respect of her tribe. Unfortunately, it all goes to hell when the humans use the knowledge he gained to destroy their sacred home, and slaughter as many as they could. The humans were the invading, occupying, and destructive force in this movie, plain and simple.
King Kong is yet another example of humans disrespecting the natural order for their own personal gain. The movie revolves around a film crew who heads out to a place called Skull Island, which was uncharted territory rumored to house a monstrous creature named Kong.
When they arrive, they quickly learn that Kong is real, and he loves the ladies! He captures Ann Darrow, a young woman selected to be the star of the movie they were filming, and the remaining crewmembers find a way to rescue her and subdue Kong, whom they take back to the United States.
Kong is presented as the "Eighth Wonder of the World" while shackled on a Broadway stage. He escapes, climbs the Empire State Building, and is killed by airplane gunfire, ultimately falling to his death.
The closing line of the movie, "No, it wasn't the airplanes. It was Beauty killed the Beast," speaks volumes as to who the real monster was, and it wasn't beauty - it was man. Had they left the gigantic ape where he belonged, and not attempted to conquer nature, the mighty ape would still live, as would a score of other people killed throughout the film.
The Day the Earth Stood Still is a movie all about the fear of the unknown and xenophobia, but it's presented in a science fiction setting that establishes mankind as the real monster. In the movie, an alien shows up to greet humanity and offer the dominant species of planet Earth a means of interstellar communication.
Instead of accepting this gift with open arms, the frightened humans shoot him. He recovers and spends some time observing humanity for a little while. He eventually shows the people of Earth that he means business by disabling all human technology with the exception of planes in flight, hospital equipment, and other things that would otherwise cause harm.
Humanity didn't take kindly to that gesture, so the alien is shot once more, but this time, he is killed. Before ultimately dying, he recovered with the help of his robot companion, Gort. He then scolded humanity for its violence and warlike ways, suggesting that the interstellar community might have to eradicate them so their aggressive manner won't infect other species spread about in space. "Your choice is simple: join us and live in peace, or pursue your present course and face obliteration. We shall be waiting for your answer."