Aliens and monsters are an incredibly important part of the Sci-Fi

genre, but there are many such beings introduced in science-fiction films that simply wouldn’t stand a chance against humanity, with its technology and military resources. Moreover, many of these aliens have weaknesses that would make fighting back simple, or even trivialize any threat of an invasion. Despite this, there are still many alien movies that manage to terrify viewers with their seeming invincibility.

Some easily defeated monsters, mostly alien invaders, stand in stark contrast to other sci-fi monster movies, which make their antagonists a much bigger threat. Films like The Thing show just how frightening the unknown can be, as well as how difficult a monster can be to defeat with a little creativity. Yet many alien-focused films are still sci-fi masterpieces, making them well worth at least one watch.

10

Shampoo Is ᴅᴇᴀᴅly To The Aliens

Evolution (2001)

Evolution begins when a group of alien microorganisms make their way to Earth on the back of a meteor. However, when scientists go to investigate the site of the meteor’s crash, they discover that the organisms have begun to evolve over a matter of a few days. The process of evolution, which would normally take thousands of years, allows these aliens to quickly become a threat to the scientists investigating them.

Although they are faced with the frightening idea that a living thing could evolve in such a short time, the villains of Evolution have one distinct weakness that makes protection against them an easy feat. These aliens are weak to a substance known as selenium, which is commonly found in products like Head & Shoulders shampoo. This allows the cast to quickly neutralize the biggest of the aliens, injecting it with the shampoo itself to kill it.

9

Small Creatures Would Stand No Chance On A Wide Scale

Critters (1986)

Small creatures aren’t necessarily harmless because of their size, but they typically need to have some additional abilities. Following a group of fuzzy beings known as the Krites, Critters shows what is essentially their prison escape attempt before crashing on Earth. From there, they harᴀss the Brown family on their farm in Kansas. Not only do the Krites eat one of their cows, but they also attack and kill a boy named Steve.

Despite the violent nature of the Krites, the movie simply does not succeed in making these small aliens appear threatening. The Krites do not have any special powers aside from their violence, and because of this, it would be relatively easy for humanity to defend against the Krites on a wider scale. They are killed relatively easily in the film, with the Browns using fire to finally defeat them.

8

Yodeling Brings The Downfall Of The Martians

Mars Attacks! (1996)

One of Tim Burton’s classic films, Mars Attacks! tells the story of Earth’s desperate defense against a Martian invasion. Shown in what are often goofy and increasingly ridiculous scenarios, the Martians attempt to take over by attacking the American government directly. This leads to a full-scale invasion, with the Martians using their superior technology to work their way toward what initially seems to be a quick victory.

It doesn’t take long for the aliens to meet their defeat, however, as the Martians have one key weakness that would make any invasion a losing battle. In what swiftly becomes a funny twist, the Martians are susceptible to the high frequencies found in yodeling music. This immediately pushes the Martians back, as even hearing this yodeling causes so much pain that their heads explode.

7

Bacteria Kill These Martian Aliens

The War Of The Worlds (1953)

In what has been a classic for decades, The War of the Worlds depicts yet another war between Earth and Mars. Based on the original novel by H. G. Wells, the movie begins with a sudden invasion as a Martian ship crashes down in America. Humanity is initially on the back foot, unable to fight back against the technological superiority they are faced with from the Martians.

The Martians depicted in this film are much more frightening than those seen in Mars Attacks! due to the fact they are immune to whatever humanity throws at them, even the atomic bomb. It is only a matter of time, however, before the Martians begin to lose. The weakness faced by the Martians in The War of the Worlds is their own immune system, which is ill-suited to Earth’s germ-infested atmosphere.

6

Psychlos Cannot Breathe Earth’s Atmosphere

Battlefield Earth (2000)

Taking place in a world that has already been conquered by aliens, Battlefield Earth depicts the rebellious effort that humanity puts forth after a thousand years of subjugation. Inspired by the Declaration of Independence and human history, a group of rebels fights back against the alien force known as the Psychlos. This leads to an explosive fight, with the rebels taking one of the security chiefs captive.

Even though the Psychlos are depicted as a terrifying force with a thirst for violence, there is one important factor that makes their initial subjugation of Earth less than believable. It is crucial to their efforts that the Psychlos cannot breathe in Earth’s atmosphere, requiring each of them to wear a breathing apparatus to survive on Earth. This would be a mᴀssive hindrance to their invasion, making it a setback that humanity could easily exploit.

5

The Aliens Are Sensitive To Sunlight

Battleship (2012)

Based on the famous board game, Battleship is a film that takes the traditional board game formula and turns it into a big-budget action movie. It follows a naval unit that discovers an alien force in the middle of the ocean, protected by a mᴀssive force field. These aliens have arrived to deplete the Earth of its resources, forcing the military to engage them in what is essentially a giant game of Battleship.

However, it is eventually discovered that the aliens are sensitive to sunlight, something that makes fighting on Earth during the day difficult. Without visors to block out the sun, the aliens of Battleship are rendered vulnerable to any human attack. This is a force that could easily be cobatted with the right tactics, something that the film shows with plenty of explosions.

4

A Computer Virus Defeats The Aliens

Independence Day (1996)

When several alien ships appear over the Earth’s biggest cities on Independence Day, the military is immediately called into action to push back the threat. However, none of their weapons seem to work against these mysterious UFOs as they wreak havoc on the cities below. Even a nuclear bomb apparently does nothing, unable to stop the invaders as the entire city of Houston is destroyed.

The military eventually devises a plan that revolves around a computer virus in the hopes that it will completely shut down the shield protecting the mothership. Incredibly, this idea works, and once the computer virus is uploaded from the inside, the aliens are attacked with nuclear weapons. If the aliens of the film are so susceptible to a computer virus, then they wouldn’t stand a chance against humanity for long.

3

One Giant Alien

Cloverfield (2008)

Filmed in an engaging found-footage format, Cloverfield shows the rise of a terrifying alien monster from the perspective of ordinary people who were on the ground when the monster attacked. This footage is eventually discovered by the United States Government, allowing them a better insight into what happened. Though not much is revealed about this monster in Cloverfield, it is implied that the monster is alien in origin.

If the Earth were to be attacked by a single, giant alien, there would be little that the alien could do to fight back against the combined forces of humanity. Humans have strength in numbers, and a single monster would eventually fall due to exhaustion or gunfire. Though this alien would likely cause much destruction, humanity would inevitably win in any similar scenario.

2

The Aliens Use Sound To See

A Quiet Place (2018)

A Quiet Place was a smash hit when it was released in 2018, showcasing a brutal post-apocalyptic future in which sound-sensitive, predatory aliens have forced humans to live in silence. The film itself focuses on one family and their survival, but it also shows that the wider world has all but fallen to these aliens. Though they cannot see, the aliens themselves are shown to be incredibly fast, being apex predators that can easily kill a human.

However, it is difficult to imagine a world where humanity allowed the problem to become this bad. While the prequel film A Quiet Place: Day One reveals more of the story, humanity should have found a way to fight back before the threat reached a boiling point. With the military and technology humanity currently has, fighting against an alien with such a specific weakness seems like something that could be manageable.

1

Water Is All It Takes To Defeat The Aliens

Signs (2002)

Directed by the iconic M. Night Shyamalan, Signs is a science fiction horror film that shows the slow, haunting invasion of a force of terrifying aliens. This is initially shown through crop circles, with the aliens depicted as being able to seamlessly blend in with the world around them. It is then that the antagonists begin to invade, going after different cities around the globe.

In another twist, it is discovered that these aliens are not immune to water, something that is abundant across the Earth. This means that humanity has a resource to fight against them that they will likely never run out of, with the rain even potentially becoming a weapon. The aliens of Signs are fighting a losing battle from the start, but despite this, it still makes an engaging sci-fi movie.