The Scariest Aliens Ever from Sci-Fi Films

Event Horizon Force

If you want to travel fast across the universe, this sci-fi movie says, you may open up some nasty creatures in your wake. In "Event Horizon", an unwitting crew discovers that an experimental engine ripped open the space-time continuum and brought a monster on to the ship performing the experiment. This creature causes hallucinations and horrible deaths, and as the rescue crew discovers, destroying the ship to destroy the creature may not be an easy task.

NEXT: The Bugs from "Starship Troopers"

The Bugs from Starship Troopers

What if insects developed technology? Humans discover such a thing in the 23rd century in this movie, when they run across creatures they call Arachnids or Bugs. The bugs have several forms of attack, ranging from military grade firing equipement to claws that can cut into people's heads and eat their brains. Getting rid of them requires some extreme measures, but we'll let you watch the film to see the conclusion.

NEXT: Aliens from "They Live"

Aliens from They Live

This metaphor about the dangers of advertising explores what happens to people when aliens embed subliminal messages into the media and advertising they experience. (Which makes us wonder what these 1988 screenwriters would have done with Twitter.) This cult film includes a memorable alley brawl and a cutely outdated (but epic) struggle to disable an alien broadcast signal.

NEXT: "Cloverfield"

Cloverfield

This "found footage" movie shows a huge monster attacking New York City. The creature breaks apart the Statue of Liberty and the Brooklyn Bridge, killing people as it wreaks damages. Worse, little "parasites" fall to the ground from the big monster, attacking nearby humans. The bites are fatal, causing people to bleed and eventually explode. Not a great way to make first contact, is it?

NEXT: "The Andromeda Strain"

The Andromeda Strain

This story (which was both a Michael Crichton novel and a feature film) shows scientists struggling to contain a deadly extraterrestrial microorganism discovered in Arizona. They kill humans through blood clotting, although some people seem to be immune to the attack. The science in this film is very impressive, with discussions of DNA and the building blocks of life -- echoing research done by astrobiologists today.

NEXT: "Pitch Black" Aliens

Pitch Black Aliens

The aliens in this movie make their first appearance when in the distant future, a spaceship makes a crash-landing on an alien planet after being struck by comet debris. These aliens are quick to eat people alive, being particularly active during eclipses and when women are present (due to some facets of female biology). Escaping from these crafty creatures is no easy task.

NEXT: Mr. Gray and aliens from "Dreamcatcher"

Mr. Grey from Dreamcatcher

Dreamcatcher (both a science fiction film and a Stephen King book) follows four friends struggling to survive after parasitic aliens attack. The aliens – which look a bit like sea creatures – not only kill humans, but also lay eggs in them. It also features a large alien called Mr. Gray, who can talk with people, possess bodies and bite humans in half when he gets angry.

NEXT: "The Blob"

The Blob

This classic sci-fi film shows an alien – which came to Earth on a meteorite – eating people and growing bigger with each successive gulp. It terrifies a couple of small Pennsylvania communities, oozing under doors or moving around buildings as it needs to hunt more prey. The end even includes a famous reference to climate change; be sure to watch it.

NEXT: Speilberg's 'War of the Worlds' Martians

Speilberg's 'War of the Worlds' Martians

The 2005 adaptation of a famous H.G. Wells film is a truly terrifying take, when aliens burst from the ground in war machines and utterly devastate city infrastructure using machinery. They make use of human bodies for evil ends. Their presence also appears to influence the weather, including lightning strikes and making planes fall out of the sky. Worse, the aliens are trying to grow a plant called "red weed" that is eating up the trees it encounters.

NEXT: "The Body Snatchers"

The Bodysnatchers

The human race faces extinction in this classic story, when seeds from space invade Earth. As people sleep, the seeds replace those folks with exact duplicates (turning the real humans into dust). The duplicates have a five-year lifespan and are unable to have children, and their plan is to kill humans and then use up resources. The 1955 novel was so popular that it's been adapted four times in film, with the latest in 2007.

NEXT: "Fire in the Sky" Aliens