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Even those too young to recall the original 1983 miniseries can guess the slippery intentions of ABC's new Visitors, who drop out of the clouds to replenish their pantry supplies. A good rule of thumb: Beware any extraterrestrial, no matter how sexy (like Morena Baccarin), who utters phrases like, ''Don't be frightened. We mean no harm.''
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Michael Bay's relentless action film breathed life into plastic toys born in the 1980s. But there was more to the film than Megan Fox. Ba-dum-bum. Fox, Shia LaBeouf, and the other mortals were simply overwhelmed by Bay's awesome CG Autobots and Decepticons, who turned Earth into a battleground during their hunt for something called an All Spark.
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As if storms in the aftermath of Katrina weren't frightening enough, Hurricane Eve brought mysterious orbs of lights and bizarre happenings to a devastated Florida town — at least according to this short-lived ABC drama. People began to change, including Sheriff Tom Underlay (a creepy William Fichtner). Human-alien hybrids appeared, but just as the first season got interesting, ABC pulled the plug, leaving us to wonder for eternity: Sheriff Tom: Hero or villain?
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THE X-FILES (1993-2002)
No conspiracy was too small for the investigators of the X-Files, the FBI's unsolved cases involving paranormal activity. Fox (David Duchovny) believed in aliens and in a government conspiracy to cloak their powerful influence on human affairs. His levelheaded partner, Scully (Gillian Anderson) was a skeptic, at first, but during their long quest, the two discovered even more truth than they bargained for. (Including, yes, aliens.)
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INDEPENDENCE DAY (1996)
Aliens have been attacking the Earth pretty indiscriminately since the early days of Hollywood, but Roland Emmerich's megablockbuster marked the first time they actually planned ahead to target the world's most postcard-friendly buildings for total annihilation. Hang on a sec — did anyone ever stop to wonder if maybe these guys were just clumsy space tourists who accidentally hit the ''apocalypse death-ray'' button instead of the ''camera shutter'' button on the UFO dashboard? I mean, who hasn't done that?
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WAR OF THE WORLDS (2005)
Spielberg's adaptation of H.G. Wells' alien invasion novel (by way of Orson Welles' 1938 radio play) was an apocalyptic pulse-racer about a man (Tom Cruise) protecting his kids while the world is attacked by some not-so-cute ETs.
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MARS ATTACKS! (1996)
Taking a cue from Ed Wood's trashterpiece Plan 9 from Outer Space, Tim Burton amped up the camp for this goofy sci-fi thriller, which paired a B-movie story line about trigger-happy aliens with an A-list cast that included Jack Nicholson and a pre-SATC Sarah Jessica Parker.
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STARSHIP TROOPERS (1997)
The aliens in Paul Verhoeven's spectacularly gory space opus aren't lanky green mutes or glowing orbs or humanoid imposters. They're bugs — giant, man-eating things with razor-sharp spider legs ready to impale the earthlings (including Casper Van Dien and Denise Richards) who are sent to squash the creatures' interplanetary feeding frenzy.
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INVASION OF THE BODY SNATCHERS (1978)
In this remake of the 1956 horror classic (far superior to 2007's The Invasion), aliens slowly overtake San Francisco by replacing its citizens with pod-grown clones. The movie's icy suspense and moody frights would serve as a model for later paranoid fantasies like Battlestar Galactica.
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THE QUATERMASS XPERIMENT (1955)
Contrary to what Hollywood has taught us, aliens don't just attack the United States. This British horror pic (the X in the title was a nod to the country's new adults-only X rating) chronicles the chilling aftermath of a failed experiment in which three astronauts are sent into space — but only one makes it back alive. And there's something odd about him...
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This white-knuckle suspense thriller from M. Night Shyamalan made use of the horror-logic of Spielberg's Jaws: The less you show, the scarier it is. With an alien invasion threatening the human race, a retired priest (Mel Gibson) tries to defend his home from the marauding creatures, which are only shown in fleeting, fuzzy glimpses. All the better to keep you squirming in your seat.
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THEY LIVE (1988)
John Carpenter's bizarro political satire starts off with a conceit that's almost as frightening as it is funny: What if the world's leaders were all space creatures intent on bending the human race to their will? The story follows Nada (Roddy Piper), an unemployed schmuck who moves to L.A. looking for work — only to come across a pair of sunglasses that let him see the aliens' true form.
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MEN IN BLACK (1997)
The genius twist in Barry Sonnenfeld's dark comic blockbuster: The aliens aren't invading — they're already here, most of them living peacefully as our friends, teachers, and cab drivers. And apparently Will Smith is the only thing standing between one particularly nasty ''bug'' (a wiggly Vincent D'Onofrio) and the destruction of the world. Good thing Wills got some hands-on experience in Independence Day.
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THE ADVENTURES OF BUCKAROO BANZAI ACROSS THE 8TH DIMENSION (1984)
Explaining the plot of this sci-fi-rock-action-spoof-thriller-epic is nearly impossible, but here's the gist: Rock star/scientist Buckaroo Banzai (Peter Weller) ends up in the midst of an interplanetary war and has mere hours to save the Earth from complete destruction.
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THE BLOB (1958)
Terror ensues after a meteorite deposits some particularly lively (and hungry) goop near a small town. The movie has gotten campier with age, but anyone can enjoy the timeless pleasure of watching a young Steve McQueen play the boy who cried ''Blob!''
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An intergalactic portal transports a team of scientists to a distant world that looks like a futuristic ancient Egypt (the oxymoron actually makes sense in the movie). Equal parts Indiana Jones and Blade Runner, Stargate developed a cult following that stuck with the story and its characters through a slew of cut-rate sequels and cable-TV series.
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SUPERMAN II (1980)
Some consider this sequel to be a little more...well, super than its 1978 predecessor thanks to a moving storyline in which Superman (Christopher Reeve) gives up his powers to be with Lois Lane (Margot Kidder). But when a trio of troublemakers from Krypton team up with Lex Luthor (Gene Hackman), the Man of Steel is forced to make a tough choice between love and loyalty.