While intelligent life beyond planet Earth has yet to be discovered (depending on whom you ask), there’s no denying that alien lifeforms are alive and well in the world of movies. Cinemagoers have been fascinated with little green men and flying saucers since the early days of black and white sci-fi pictures, and their appeal has only escalated since. In just a few short months, director Ridley Scott will release the highly anticipated Alien: Covenant, the latest entry in the Alien franchise which was conceived 38 years ago.

Science fiction is one of the most imaginative movie genres out there, and that imagination has built some of the most creative alien designs anyone has ever seen. With so many fantastic extraterrestrials to choose from, we thought it would be fun to look back at the most iconic aliens in movie history. The following otherworldly creatures on this list are the best of the best that sci-fi has to offer. Hairy, slimy, cuddly, disgusting, friendly or downright frightening, they can either come in peace or leave the world in a wake of destruction just as long as they have cemented a place in pop culture while doing it.

Here are the 15 Most Iconic Movie Aliens.

15. Groot (Guardians of the Galaxy)

Groot Looking At the Camera

Kicking off our list is one of the newest alien lifeforms to grace movie screams, although he’s certainly older than his feature debut in 2014's Guardians of the Galaxy. Groot’s first appearance comes all the way back in 1960 with Marvel’s science-fiction anthology Tales to Astonish, where the sentient tree-like creature was actually an invader that intended to capture humans for experimentation. Since then, Groot has become a hero and a member of the Guardians of the Galaxy, a rag-tag team up of intergalactic misfits.

The live-action adaptation of Guardians hit theaters in the summer of 2014 and dominated the box office, with Groot becoming a pop culture sensation overnight. It’s not hard to see why; the friendly-natured talking tree provided some of the best comedic moments of the movie, as well as some of the most emotional. Not bad for a guy that can only say his own name.

This year’s Guardians of Galaxy Vol. 2 will bring everyone’s favorite botanical alien back, only this time he’s smaller and cuter than before, which will no doubt only increase his already enormous popularity.

14. Audrey II (Little Shop of Horrors)

Little Shop of Horrors

Aside from The Rocky Horror Picture Show, few movies have earned a bigger cult fan base as Frank Oz’s remake of Little Shop of Horrors. The horror/musical stars Rick Moranis as a nerdy florist who one day discovers a new mysterious plant that he names Audrey II. However, unlike roses or tulips, Audrey II survives off of human victims rather than sunlight and rain water. This carnivorous alien plant has a taste for blood and often breaks into tune about her evil appetite.

While Audrey II isn’t one of the more realistic looking aliens (it’s a giant murderous plant that sings), she nonetheless has cemented her place in pop culture. Based on the off-Broadway show, the character is hugely entertaining, combining the best parts of sci-fi, horror, and comedy. Even though Rick Moranis and Ellen Greene are solid in the lead roles, Audrey II steals every scene she’s in, and with such incredible animatronic special effects and catchy tunes about eating people, how could she not?

13. The Worm Guys (Men in Black)

It’s easy to forget from the less than stellar sequels, but the first Men in Black was quite the hit back in 1997. It had one of the best unexpected comedic team-ups with Will Smith and Tommy Lee Jones, a tongue-and-cheek script, solid special effects, and an overabundance of really cool looking aliens. While everyone remembers the alien Frank the Pug, the standout extraterrestrials from this sci-fi comedy has to be the Annelids, better known as “the worm guys.”

These smart-mouthed aliens first show up when Will Smith’s Agent Jay is still in disbelief of the fact that there are actual aliens running around Manhattan. Tommy Lee Jones’ Agent Kay nonchalantly takes his protégé into the breakroom, where the dumbfounded Jay comes across a group of coffee-drinking, cigarette-smoking worms. With just that short scene, the worm guys earned their place as one of the funniest side-characters in sci-fi history, enough for some fans to even ask that the bizarre caffeinated worms get their own spinoff movie.

12. The Na’vi (Avatar)

Avatar Zoe Saldana And Sam Worthington

James Cameron has proven time and again that he is one of the best sci-fi directors of all time (some would say that he is the best). In 2009, he released his box office behemoth Avatar to mass audiences, which became a global sensation during its lengthy theatrical run. It quickly became the film that audiences had to see for themselves for its innovative special effects, which included breathtaking CGI creations of the film’s primary aliens, the Na’vi.

These blue humanoids have since become a staple of modern movie aliens thanks to their sleek design and impressively built lore. The emotional expression from the alien creatures is especially impressive when you remember that the performances are all motion captured. Since the release of Avatar, the Na’vi have become one of the most recognized movie aliens in the world, parodied in everything from Family Guy to Ben Stiller at the Academy Awards. You know you’ve made it big when Stiller paints himself blue for a four minute skit at the Oscars.

11. Space Nomads (Independence Day)

Alien Queen in Independence Day: Resurgence

Let’s all pretend for a minute that Independence Day: Resurgence never happened. Have you wiped it from the databanks in your mind yet? Good, now we can all agree that the Space Nomads from 1996's Independence Day are some of the coolest, diabolical space invaders in cinema history. After systematically placing all of their enormous spaceships above Earth’s biggest cities, the Space Nomads effortlessly wipe out a huge chunk of the world’s population, and this is all before we get our first good look at them.

Encased in a bio-tech armor suit, these invaders are creepy, powerful, and downright frightening. Who could forget that spine-chilling autopsy sequence where one of the aliens wipes out an idea room of scientists, or their first welcome to Earth, courtesy of a sucker punch by Will Smith? The Space Nomads have definitely earned a place in pop culture history, particularly for their undying motivation of wiping out our entire history from existence.

10. Arachnids (Starship Troopers)

Starship Troopers 2

Paul Verhoeven’s razor-sharp satire of military life, Starship Troopers tells the story of one Johnny Rico, a kid fresh out of high school who decides to enlist in the quasi-futuristic marines. Just when it looks like Rico is about to quit the military life, his hometown gets wiped off the face of the Earth by giant space bugs who declare war on mankind. Fueled by revenge, Rico and his compatriots go into battle against the Arachnids, a species of carnivorous space insects.

Mean, violent, and just plain scary looking, the Arachnids from Starship Troopers aren’t the type of aliens you’d want to mess with. These things are gigantic in size and can slice right through you without thinking twice. Even worse is that the fact that the Arachnids have humongous numbers and attack in drones, overpowering any troop that dare try and oppose them. Since their debut in Starship Troopers, this terrifying alien race has served as the blueprint for a slew of other movie aliens, including inspiring the design behind the MUTOs in 2014’s Godzilla reboot.

9. Shapeshifter (The Thing)

The Thing 1982 Norris Monster

The Shapeshifter from John Carpenter’s The Thing is a unique entry on this list in that you never actually see what its true form looks like. A master alien when it comes to surviving, its unique ability to take the shape of other living organisms helps this terrifying creature to adapt, blend in, and take over any planet of its choosing.

Though you never get a good look at the alien’s actual form, the audience is treated to one bizarre character design after another as the Thing assimilates various victims. Each part of the creature can morph into a separate entity of its own, including a spider-like head that sprouts legs and dashes off after its body is charred to a crisp, or a stomach with a giant mouth of razor-sharp teeth. Its final form, which is a hodgepodge of horrific images of past hosts, is particularity frightening, and one that still haunts the memories of moviegoers to this day.

8. Prawns (District 9)

District 9 Prawns

Neil Blomkamp shot onto the scene in 2009 with District 9, an intriguing sci-fi flick about a race of alien refugees who are forced to live in slum-like conditions after landing on Earth. This race of extraterrestrials is nicknamed “Prawns,” not only because they look like giant shrimp, but due to the fact that the people of South Africa (where the aliens inhabit) coined the name after a species of large crickets called parktown prawn.

They may not be the best-looking creatures, but the Prawns have marked their place in sci-fi movie history thanks to Blomkamp’s socially conscious film. Although they may look frightening at first glance, the Prawns are actually quite sympathetic. They’re malnourished survivors who are forced to live in a rundown government camp called District 9, and only after a government becomes involved in their plight does the world decide to take in an interest in these forgotten creatures.

7. Superman (Superman Series)

Superman's suit in Man Of Steel

Superman may be the most human looking alien on this list, yet still remains as one of the most iconic. Unlike many members of the Justice League, the Man of Steel is unique in that he was not born on this planet. His home world is the planet Krypton, which was fatally destroyed, wiping out almost every inhabitant. As one of the last survivors of his race, Superman makes Earth his new adoptive home when he’s taken in by the Kents, later becoming the famous superhero who stands up for truth, justice, and the American way.

Faster than a speeding bullet and stronger than a locomotive, Superman is one of the most recognizable comic book heroes in history, so it only makes sense that his movie counterpart would be in the same league. Everyone’s familiar with his patented abilities of heat vision, super strength, and flight, as well as his costume made up of a blue suit, red cape and yellow utility belt (with or without the red undies). He’s the original alien superhero, and his cultural status has never been bigger, especially given the massive anticipation of whether he'll show up or not in the upcoming Justice League movie.

6. Spock (Star Trek)

Leonard Nimoy and Zachary Quinto as Star Trek's Spock.

Though he’s another alien that doesn’t really look like an alien, Mr. Spock is still one of the most famous extraterrestrials in pop culture, especially amongst Trekkies. With his pointed ears and signature Vulcan salute, he’s the face of the Star Trek franchise, played in the original series by Leonard Nemoy and by Zachary Quinto in the modern movie reboots.

Spock might be one of the most beloved aliens in movie and TV history. The half-human, half-Vulcan has been the first officer of the starship Enterprise since Star Trek’s conception in 1966. Together with his friend James T. Kirk, he boldly goes where no man has gone before, visiting foreign alien worlds and armed with nothing but his Vulcan nerve pinch. With such a long history with the Star Trek franchise, there’s no doubt in our minds that the character of Spock will live long and prosper for many years to come.

5. Chewbacca (Star Wars)

Star Wars: Chewbaccas, played by Peter Mayhew and Joona Suotamo

Aside from being one of the hairiest movie aliens, Chewbacca is, without a doubt, also one of the most iconic. First introduced in George Lucas’ Star Wars (you may have heard of it), this Wookie is the faithful sidekick to Han Solo. Though his English vocabulary is limited to a few grunts and growls, Chewbacca is one of the most charismatic aliens in all of Star Wars.

Just as good a marksman as he is a co-pilot to the Millennium Falcon, Chewbacca has provided the epic space franchise with some of its best moments. Whether it's his playful banter with Han Solo ("Laugh it up, fuzzball."), his uncanny ability to fix the hyperdrive in a pinch, or taking out Storm Troopers with his iconic bowcaster, Chewbacca has proved to be one of the most resourceful characters in Star Wars, and one of the most popular with fans.

Prepare to get your Wookie fix when Chewbacca returns to theaters in this year's Star Wars: The Last Jedi.

4. E.T. (E.T. the Extra Terrestrial)

E.T. lifting his finger

Not all movie aliens are terrifying invaders. Some of them are just friendly passer-byes who are just looking for a helping-hand, such as the case in Steven Spielberg's E.T. the Extra Terrestrial. This classic family movie from 1982 sees a gentle alien from another world stranded on planet Earth. He is then befriended by Elliot, a kid from the suburbs who agrees to hide the little guy while E.T. tries to contact his alien compadres.

Being that E.T. the Extra Terrestrial was one of the biggest movies of the 80s, E.T. himself has remained as one of the most iconic aliens of all time. Though he looks a little frightening at first glance, this passive movie alien has broad appeal to adults and kids alike. Whether its his telekinesis making things float around Elliot's room, his heartbreaking final moments with Elliot, or the iconic shot of the bike drifting across the backdrop of the moon, E.T. has provided moviegoers with more classic cinema moments than most of the other aliens on this list combined.

3. Predator (Predator Series)

Predator

Lethal, persistent, and sporting the most high-tech hunting hear in the entire galaxy, the Predator is the apex killer when it comes to otherworldly bounty hunters. He's the main antagonist of John McTiernan's 1987 action classic, Predator, in which a team of tough-as-nails commandoes are hunted down in a Guatemalan jungle by this alien beast. The team is picked off one-by-one until their leader, Dutch (Arnold Schwarzenegger in his prime), is the last one standing to go toe-to-toe with his alien stalker.

The Predator has so many iconic attributes, it's hard to pick where to start. Audiences are more than familiar with his heat-seeking helmet, his automatic targeting laser gun and, of course, his signature alien dreads. Perhaps the Predator's most iconic look is what lies beneath his mask. The alien's snarling, horrific facial structure that was first created by effects wizard Stan Winston is, to this day, one of the most widely recognized in all of movie aliens. As Schwarzenegger so eloquently put it, the Predator is "one ugly mother f*****."

30 years after his cinematic debut, the Predator will be stalking even more victims when he returns to theaters in next year's The Predator.

2. Yoda (Star Wars)

Yoda The Force Star Wars

Cinema history is filled with aliens who are little green men, but none of them are more famous than Yoda, the Jedi master who first showed up in 1980's The Empire Strikes Back. At first thought to be a senile old man, audiences were just as stunned as Luke when they learned that this short guy was one of the most powerful force-wielders of all time.

What Yoda lacks in height, he more than makes up for with his wisdom and insanely skilled knowledge of the force. He instantly became one of the most iconic characters in all of Star Wars history thanks to his signature backwards talk, his inspirational one liners ("Do or do not. There is no try.") and incredible feats of strength, like being able to pull Luke's crashed X-wing out of the swamp. Although he finally became one with the force at the end of the original trilogy, Yoda is so popular that he still manages to show up in everything Star Wars, including the latest trailer to this year's The Last Jedi.

1. Xenomorph (Alien Series)

Alien - xenomorph

What makes a great movie alien? Is it its otherworldly design or appearance? Is it the character's ability to remain relevant in pop culture? If there is one alien that has stood the test of time and continues to draw massive appeal, then it has to be the xenomorph from the long-lasting Alien franchise. To be it quite bluntly, no other cinematic terrestrial comes close.

Making its debut in 1979 with Ridley Scott's Alien, the xenomorph burst onto the scene in one of the best movie entrance's of all time when it literally burst from Kane's stomach. With it's razor-sharp tail, tiny mouth appendage, and acidic blood, it hunts down the crew of the Nostromo as audiences terrifyingly looked through the cracks of their fingers in theaters. The xenomorph became an even bigger cultural symbol in James Cameron's sequel Aliens, which is still referred to as one of the best action movies of all time. Thanks to its nightmarish look conceived by H.R. Giger, the xenomorph has remained as one of the most enduring creatures in movie history, and gets our vote as the most iconic movie alien of all time.