Alien (franchise)/WMG

Xenomorphs are able to impregnate human hosts through sexual reproduction just fine, and often do so when the facehugger/chest-burster method is unfeasible.
Several sources corroborate this. A scrapped scene in the first Alien movie has a drone raping a human soldier. In the Aliens: Book II comics, it's mentioned that random drones are created on occasion to specifically mate with the Queen, fighting to the death among themselves for the privilege and being snuffed out by the Queen (like with Praying Mantises or Black Widow Spiders) after the deed. The Stan Winston Creations version of the Alien Drone was to be included with a torso-length penis, and the hybrid "Newborn" Xenomorph in Alien: Resurrection was to be hermaphroditic, with both sets of genitals. Clearly, the phallic references in the movies weren't meant to stop at innuendo, but to be shown as another aspect of Xenomorph reproduction outside the chest-bursters and facehuggers. Facehuggers are needed because they're the primary form of reproduction; the drones mate with the Queen to produce them, but they can rape and impregnate human hosts themselves if the facehugger/chest-burster method cannot be implemented.
 * Alternatively, they are capable of sexual reproduction among themselves, but not with other species. They just rape humans for fun.
 * Squick.
 * Queens are completely asexual: they never mate. Novels and comics are often contradictory and so can't be relied on (Ripley coming Back from the Dead twice is a good example). This probably includes the scene where in the novelization, although it was pretty sick.
 * No, the "rape" scene wasn't cut from the first movie. There was an offscreen moment in Alien where the monster is heavily implied to
 * Perhaps the alien was mounting her to prove its "dominance" the way male and female dogs do.
 * How would such a pregnancy work? Like Species? Unfortunately,
 * Or it was doing it for fun. Squick!
 * Someone actually wrote a fanfiction called Aliens Versus Serenity that involved The story violated canon in lots of other ways, though, and added some pointless new characters with no explanation.
 * H.R. Giger himself has confirmed that the alien is male,complete with equipment. He didn't come out and say this: he drew it. Sil even made an appearance with it. That puts poor 's plight in a whole new light.
 * Considering the biological weapon WMG, this may very well be the case. The face huggers are the method of infection other species, one time use to get one drone-hybrid. Drones then could very well mate with their "host" species to speed up infestation.
 * Considering the biological weapon WMG, this may very well be the case. The face huggers are the method of infection other species, one time use to get one drone-hybrid. Drones then could very well mate with their "host" species to speed up infestation.

The Xenomorphs are a biological weapon.
Every facet of them seems specifically designed to wipe out any colony, starship, or large planet their eggs are dropped on. This is a few steps shy of canon; canon does not rule out their evolving this way. But, given their efficiency, this is more probable.
 * What good would replacing one enemy with an even stronger and more dangerous one do?
 * The Xenomorphs would be landlocked and unable to use (external) weapons. Bombardment from a safe distance would work more smoothly on them than it would on a sentient technological race ("It's the only way to be sure."}, for they'll have no anti-aircraft missiles.
 * ^ Not to mention they stick closely to their hives with only a few scouts out for more hosts/food. It is easier to replace a spread out population of tens of billions to one of billions that reside in large hives that are easy to spot and destroy with orbital bombardment.
 * The Aliens have a really short life-cycle, or at least they did in the first film. By the end of the film, when it's hiding in the shuttle and not doing a hell of a lot when Ripley disturbs it, it's getting ready to die.
 * Or is just sleepy - it had a long and busy day after all.
 * And in Aliens they're in hibernation as there is a distinct lack of human hosts for them. Only a few are active, and at night; otherwise Newt would have been long dead.
 * There's also that if you can genetically engineer the Xenomorphs into existence, you can potentially build in any number of hidden weaknesses you can use to get rid of them. The Space Jockeys probably had some tailored anti-Xenomorph chemical weapon they could just use to flood the zone after the Xenos had done their work of wrecking their enemy's colony.
 * This is only a problem if you assume the Space Jockeys want the planets they've bombed. Area denial might be the more important concern.
 * Maybe the race that developed them put a biological receptor into them so a signal could be sent out to destroy the whole hive without bloodshed - or immobilize them en masse. This device is probably long lost to history though... or the Weyland/Yutani corporation salvaged it from the derelict.
 * Ridley Scott mentions this in his DVD commentary. The derelict was a bomber used for egg delivery.
 * I guess we'll find out when Prometheus premieres...
 * According to Prometheus, it seems that the Jockeys are bent on destroying all sapient life from the cosmos for reasons unknown, using numerous bioweapons, including the xenomorphs. What their motivation could be is a total mystery, but they seem to utterly suck at internal security protocols.

The Xenomorphs are the descendants of the Bugs from Starship Troopers.
After losing their first war with Humans, they adapted. They got rid of the Brain Bug (which was clearly an idiot anyway). They developed a more streamlined shape somewhat similar to their foes (jaws, hands, bipedalism), acid blood for close defence, and a method of reproduction that involved using their enemies to their own advantage. Meanwhile, humanity spread further out into space until they had to use coldsleep chambers on long-range starships. Earth's world government dissolved into national governments; the resulting wars caused their military forces to re-acquire tactical skills.

The Predators were created by the same race that made the Aliens, to hunt them down after they'd gotten out of hand.
The Predators definitely have some kind of relationship with the Aliens. The fact that their blood is able to neutralize the Aliens' acid blood can't be coincidence.
 * So, if the Aliens have acid instead of blood, does that mean the predators' blood is a base?
 * That makes "If it bleeds, we can kill it" rather bitterly ironic.
 * Even moreso once you consider that bases are just as corrosive as acids. (e.g. Fight Club lye incident)
 * Alternatly, the Predators were once a slave race that rebelled and the Aliens were bred to destroy them.
 * This theory reminds me of the background stories of the Protoss and Zerg from Starcraft.
 * This troper and his brother believed that the Predators created the Xenomorphs as the perfect hunting game. This would coincide with the "The Xenomorphs are a biological weapon" theory mentioned above.
 * At least one of the Aliens vs. Predator novels had a plot based around this, where the Predators hunted the Aliens they had dropped in themselves as some sort of initiation rite, not counting on it being a human colony.
 * The Dark Horse novels advanced the theory that the Space Jockeys (the creators of the Alien) once visited the Predator homeworld. The ship was captured by the Predators, who then reverse engineered it to create a technologically advanced civilization. This neatly explains why a culture with more advanced techology than our own has a culture closer to hunter-gatherers, but it doesn't explain why the Predator technology is not biological in nature like Space Jockey technology.
 * Furthermore, when the Predators first encountered the Aliens, they got the bright idea to use them as game animals for their rites of passage. And when they encountered humans, they set themselves up as gods and have since used Earth as an hunting ground even after their cults died out long ago.

The Aliens are an evolutionary combination of a dinosaur and a jellyfish.
The non-Facehugger Xenomorphs can quite easily be seen to fit, say, the model of a velociraptor, though tweaked into something a bit more disturbing. Where, then, does the Jellyfish come from? Jellies, along with Anenomes, Coral, and Hydra, are Cnidarians. Cnidarians are notable in that most of them have a life cycle that involves two different types of organism, though one is usually dominant. Instead of "impregnating" humans, Facehuggers (the Zygote form of the Xenomorph Cnidatian) shoot out a Larva which develops into a parasitic polyp which buds a single Chestburster before dying with its host.
 * That similarity doesn't have to mean they're literally related to cnidarians, any more than their parasitoid gestation makes them related to wasps. Even on Earth, alternation of generations is hardly unique to jellyfish. Look out your window, and you'll see thousands of organisms that alternate between one form and another, with every generation: we call them "plants".

The Aliens are tumors.
Instead of eggs, the Face-huggers "impregnate" their hosts with a mutagen that causes a growth to form inside the body. In Real Life, sometimes people develop growths called teratomas which contain things like teeth or vestigial organs which have formed inside them due to weird genetic phenomena. The Aliens use a controlled form of this process, causing a growth that develops teeth, bones, and organs; it eventually becomes capable of living apart from its host, rips its way out, & grows into a monstrous killing machine. This explains why Aliens grown from different species have different characteristics, which doesn't make much sense if they're just eggs implanted parasitically.
 * In Superman comics, an Xenomorph-like creature called Kancer came out of Superman. It was born from a kryptonite-induced tumor.
 * This also fits with how a clone of Ripley still develops a Queen.
 * This is disproved rather graphically in Requiem. Although that movie had a lot of problems.
 * It's still possible the developing embryo uses a virus to prevent the host's immune system from attacking it. It would pretty much have to use specialized viruses to both sample the host's DNA and alter the host to suit them. This also opens the horrifying possibility that if a person who was previously a host has children, then his or her children will eventually develop their own chestbursters without having to be attacked by facehuggers. If that's the case, Ripley 8 is in for a horrible surprise if she ever tries to start a family.

The Aliens are lower-level Anti-Spirals.
First contact with the xenomorphs occurred shortly after interstellar travel became feasible. They automatically attack humans, but ignore animals such as good old Jonesy.
 * But, wait....didn't one of the face-huggers impregnate a DOG (Ox if you watch the Directors Cut} in the third movie? Likewise, the alien in the first movie most likely attacked humans because it saw them as a bigger threat than a cat. Which is more likely to kill you if you were a Xenomorph: a cat whose only defenses are sharp claws and teeth, or a highly-intelligent life-form that has the brains, resources, and weaponry available to easily dispatch you?
 * It ignored Jonesey because a kitty is too small to support a Chestburster. As a hive organism, its reproductive urge is stronger than individual survival instincts; it seeks hosts first and foremost, with threat level being a secondary consideration.

The Aliens are the victims in the films, not the villains.
If you think about it, in all of the films, the aliens are never shown as malevolent, nor do they do anything that's evil. They're just creatures trying to survive. We never see what happens if the Xenomorphs themselves are left in peace, do we? No, instead what we see is what happens when or after another life-form enters their territory.
 * Alien has the titular monster being brought aboard a ship (though the crew doesn't know it) because the evil corporation wants a live specimen to study. The alien spends most of its time attacking anyone on a ship it views as a threat since, well, everyone (except for ) is trying to kill it.
 * Aliens had the space-marines sent down to a space-colony crawling with aliens to destroy the monsters because they wiped out the human population there. Okay, fair enough....until you realize that it was HUMANS who brought the aliens to the colony in the first place.
 * And, again, we have the evil corporation (that is, Weyland-Yutani) trying to get a live specimen to study and possibly use as a sort of biological weapon.
 * The Dog-Alien AKA "Runner Alien" from Alien 3 was only trying to protect the queen-chestburster inside Ripley. It's no different from when a colony of ants or bees attacks someone/something intruding on their nest to protect their queen.
 * Alien Resurrection has the old "Let's study them" routine again. Yes, let's study the highly-aggressive extra-terrestrial life-forms. What's the worst that could happen?
 * The first Alien vs. Predator indicates that the Predators BREED (and possibly capture) queen aliens just so they can force them to lay eggs. Why? Oh, nothing, except to use as a rite of passage for teenage Predators in which those teenagers must prove themselves worthy by KILLING a full-grown alien or the imprisoned queen.
 * After I finished watching that movie, I came to the same conclusion: Predators are in fact true villains. They breed Aliens using human sacrifices as Aliens' host bodies, just so they can hunt them down as their twisted sadistic sport. Many ancient human civilizations are destroyed in the process. The Aliens are just wild animals, acting on their instincts for survival. The "civilized" Predators, on the other hand, are a nothing but bunch of aristocratic bastards. And humans are just hapless victims caught between both sides.
 * AVP: Requiem has a Predator spaceship containing facehuggers crash-land onto earth. Again, the facehuggers weren't on that ship of their own will.
 * In the novelisation of the first film, the scene in which Ash is interrogated by Ripley implies this interpretation pretty strongly, and Ripley herself advances a similar view a few times over the series. The Xenomorphs aren't evil, they're just predators doing what comes naturally in order to survive. The problem is that what comes naturally to them is rather horrible for their victims, i.e. us. It's not too dissimilar to Jaws really. The shark was just doing what it did, but that posed a threat to the humans, so they fought back. Same deal here. However it's worth noting that while the Xenomorphs are indeed arguably the victims of the series, that doesn't make them any less terrifying or deadly.

An Alien Queen might be a decent enough sort if she were raised right.
Related to the 'the Aliens are the victims' theory above, something we need to remember is that the queen of the hive, at least, is intelligent. Granted the aliens we've seen have been monsters that hunted humans, with a horrifying reproductive cycle. But consider the aliens we've seen: the alien in the first film was a drone, which appear to be nonsentient due to their willingness to Zerg rush. Without a queen, it was simply operating on it's (very very lethal) instincts. Then in Aliens, we have a queen who is essentially a feral child: we never learn at what point the swarm of drones overtaking the colony developed a queen, but it must have been after the first drones started hatching. From the time she was born she was fighting humans, and shortly thereafter she was entirely alone. Small wonder she went insane: you could almost parallel her situation to Newt's, except that Newt was 'older'. In the third it's just drones again, and in the fourth the queen had been raised in a lab being experimented on and tortured. In that case she wasn't too innocent to know better, she had LEARNED that humans are bastards. But raising xemonmorphs using animals as hosts, and actually raising the Queen instead of letting her grow up a psychopathic manchild with good reason to hate humans, might work out just fine. As long as the queen agrees that you can't use people as hosts there's really no more problem: she can raise other Queens herself, and the aliens can actually form a society with humans and each other (on a hive to hive basis). It's like Digger says: someone must teach them to be good.
 * This troper assumed the queen in Aliens was alive and well in the Space Jockey's ship during the events of Alien, she was just hibernating since the planet was barren.

The Xenomorphs are descended from the remnants of the last Tyranid invasion.
The Tyranids are a hyperevolutionary race - they adjust and adapt to any and all threats after they've been identified by hurling wave after wave of expendable 'nids at whatever obstacle they're facing. They've been strongly implied to have swept other galaxies clean of biomass to consume. What if they missed a couple of worlds and left a few Lictors lying around? What manner of killing machine would they eventually evolve into? Small nests of Tyranids are hardly unknown in the 40K universe. The Alien Queens descended from Hive Tyrants and Tyranid warriors in an attempt to re-establish the Hive-Mind, while the drones are the descendants of Gaunts. Come the 41st Millenium, the 'nids proper will return and begin the cycle anew.

Golic from Alien 3 is the Eighth Doctor
He hasn't really killed anyone and is just on the prison planet for some Doctor-ish reason. He fabricated his records. Then he went insane for a bit. We never saw him die onscreen, at least not in the theatrical cut. We never saw the Eighth Doctor regenerate. Maybe there is an Alien with Time Lord powers out there - a Doctor!Alien.
 * It could be a Post Time War Eight, driven mad by the end of the War.
 * We don't even actually see him die in the Recut, either. Presumably he got eaten when he went into the shadows, but you never know. Maybe that's how he actually regenerated into Nine -- it would partially explain why Nine is the way he is, in addition to the Time War.

The facehuggers and adult xenomorphs are envelopes to keep multiple eggs with predetermined shapes alive until they can find a species of the proper shape.
The eggs are already there, fertilized and mostly developed. The facehuggers are released based on the most common local genotypes in an effort to make it easier for the aliens to attack a given species shape. There are four-legged, muzzled aliens, two-legged aliens with a vertical-opening mouth set roughly parallel with the rest of their face, and another type with two legs and tentacles out of its head. Depending on what you believe about the predator-alien connection, predaliens may be the original form of the xenomorphs, and humanlike aliens the mid-stage adjustment between predaliens and the future humaliens. It was developed as a useful survival trait because the species the aliens originally attacked species with no sense of the Uncanny Valley, a rare trait possibly unique to humans. Being about the right shape made the aliens seem more trustworthy instead of scarier.

The xenomorphs can convert energy into matter.
We only see them growing to full size at the absurd speeds they do in places with electricity and a temple built for the purpose of raising xenomorphs for Predators to hunt. The temple provides energy through its design, and xenomorphs elsewhere just plug their tails into electrical sockets or something. This is how they get so damn big without consuming at least a human and a half of biomass.
 * Unfortunately, this creates about as many problems as it solves. The equation E=m*(c^2) shows that for the Xenomorph to gain one kilogram of mass (roughly 2.2 pounds), it would have to absorb 90 quadrillion joules of energy, which is 25 billion kilowatt-hours. To get to a full 100 pounds, it would have to absorb over a trillion kilowatt-hours of energy.
 * Alterntively, they may be able to absorb mass through other means than eating. According to some sources, the Aliens are at least partially inorganic. What may happen is they can assimilate materials from their surroundings. This is supported by the fact that the creature from the first film has a slightly metallic look to it, whereas the ones from later films who appear on actual planets look more organic. This would actually be beneficial to their stated purpose of wiping out all life on a planet, since absorbing material from the planet would give it better camoflage. It's also interesting to note that HR Geiger's original design sketches for the Chestburster were very different from the finished product. Originally it resembled a Thanksgiving Turkey, with a "head" resembling the tongue-rod. Possibly this was meant to be the creature's true form, while the phallic-headed humanoid we all know & love was simply a shell the thing build around itself.
 * Maybe they just eat and digest really fast. They could be an Extreme Omnivore who can digest anything with organic chemistry-- food supplies laid away for humans, plastics such as wire insulation (spaceships would have many miles of cable) and wall panels, IV fluid used during hypersleep, etc. Alienverse ships tend to be pretty big, there's probably more than enough carbon-based mass tucked away in bits and pieces to grow an organism that size.
 * The Extreme Omnivore bit is actually canon. Chestbursters can and will eat ANYTHING, up to and including metal that they soften with acid which they either simply spit or bite out of their own mouths. When you consider the fact that they already have insane acid for blood, it's not a huge leap of faith from that to insanely strong stomach acid.
 * Another thing that can help is assuming much of their body tissue is actually bloated with water to get size and mass, at least when first hatched: part of the reason the one in the first movie was so slow. The chestbursters come out mostly dehydrated, with hyper concentrated cytoplasm and nearly dessicated tissues, to help them fit inside their hosts. Then they soak up water to bring their tissues up to normal and radically expand like one of those foam toys. That plus Extreme Omnivore can take up a lot of the slack in the physics.

Aliens are creations of Elder Gods
They fits perfectly as one of the lesser races from Cthulhu Mythos.
 * Plus their growth rate ignores the conservation of energy, making them a violation of natural law.
 * Not necessarily, see above.
 * The fact that their design was based off a painting called the Necronomicon IV seems to support this.

Alien blood has high levels of Chlorine Trifluoride.
"This colourless, poisonous, corrosive and very reactive gas condenses to a pale-greenish yellow liquid, the form in which it is most often sold (pressurized at room temperature)."
 * Look at the evidence; Alien blood is ultra corrosive, water and sand burns in contact with it and it burns even things which have already have been burnt, those are all the Real Life properties of the chemical Chlorine Trifluoride.
 * the other wiki says:

Xenomorph blood is a pale greenish yellow liquid, and it's held pressurized in their bodies. And it steams at ambient temperature.

The Alien lifecycle explained!
Theory that attempts to explain all the various oddities of the creatures, incorporating some of the previous WMG.


 * Step 1: The Facehugger attaches itself to the host & infects it with an exotic form of engineered bacteria, cultured in the sacs near the creature's tail. This bacteria secretes a mutagen that causes an extrememly differentiated terratoma to form inside the host's body. The bacillus is capable of infesting pretty much any living thing, but the growths they spawn will necessarily vary from species to species.
 * Step 2: The terratoma develops its own organs & becomes capable of living apart from the host, emerging as a Chestburster.
 * Step 3: The Chestburster runs away & looks for a suitable place to grow. While the creature does need some biomass to sustain itself, it uses a more exotic method to grow into its next stage. The alien bacillus is also a powerful oxidising bacteria. It can break down minerals. This is the cause of the Aliens' "acid" blood. But in addition to breaking them down, under the right conditions it can also reconstitute them. This way, the Chestburster forms a shell around itself made of minerals animated by strange chemical reactions driven by bioengineered micro-organisms. This handily accounts for how Aliens are said to be partly silicon-based despite being born from carbon-based creatures.
 * Step 4: How do they get more Facehuggers? They're secondary terratomas that split off from the main one if it remains active long enough. Note how, like any terratoma, the Facehuggers also have various mundane bits where they don't belong. Fingers, a spine, etc. Once an Alien's inner terratoma has grown enough to start spawning Facehuggers, it will absorb more minerals to contain the burgeoning tumor, attaining the "Queen" form.

Aliens is a wildly historically inaccurate, racially insensitive account of what happened on Pandora.
They got the very broad strokes correct -- a mining company hires a bunch of ex-marines, they fight aliens on an alien planet, they blow the place up and flee -- but thought it'd make a better story if the marines were heroes, the aliens were vicious monsters, and the retreat was victory rather than failure. At least they correctly characterised the company as a bunch of dicks.

Weyland-Yutani wants to use the Xenomorphs against the Na'vi.
After being kicked off Pandora by Jake and the Na'vi, RDA starts looking for the perfect weapon to retake Pandora. Eventually, they get in touch with Weyland-Yutani, and learn about the Xenomorphs; a race that can decimate organic species is the perfect weapon to use against Pandora's living defenses. If xenomorphs 'accidentally' found their way onto Pandora, they could impregnate/destroy every Pandoran species, giving RDA an excuse to bomb the moon from orbit, and leave nothing but unobtainium behind. RDA offers a tantalizingly huge amount of money to Weyland-Yutani for xenomorph specimens, and this fuels their desire to acquire them.
 * Wait, did you forget that Ripley was there all along, pretending to be a scientist? because that already had happened. The Aliens had developed according to the planet's wildlife, the Na'vi called it Thanator.

The Xenomorph queen from Alien vs. Predator is still alive.
Quite simple really, we have no reason to believe sub-zero temperatures or drowning will kill a xenomorph (the ones kicked into space could be alive too). It is my belief that they "killed" the queen this way, in order to have the queen lay eggs on the ocean floor, creating some sort of shark-xenomorph, and then having a Alien vs. Jaws crossover.
 * Damn, four decades too late! In The Seventies, that idea would have rocked. Now, though, fans have been jaded by Sequelitis and the mediocrity of Freddy vs. Jason...
 * Instead of Alien vs. Jaws, what about Alien vs. The Abyss?

The aliens' acid blood isn't blood.
In the first film, they state that the Facehugger has a layer of silicon-based cells as well as carbon-based. This is actually a subcutaneous two-layer barrier containing the corrosive in small bladders just under the outer skin. Otherwise, a creature with such a radical solvent chemistry could not grow inside a human body. It also means that newborn chestbursters are probably not very acidic-- they have to eat something containing digestible silicone componds in order to form those protective cells, otherwise their own concentrated acid will digest them from the inside.

The aliens are a Series V lifeform.
The aliens fit the criteria of a Series V lifeform: they are based on silicones rather than carbon, are able to breathe in oxygenated atmospheres, and use sulfuric acid as a solvent. The only problem is that such life is designed to survive in extremely hot environments. Art Major Biology, indeed.

The Predators chose Humans as the host for their Aliens meant for rite of passage because Humankind is so damn useful
For some reason, us Humans have the perfect physiology to host Aliens. We are big and strong and full of enough nutrition to make for a good challenge over smaller, weaker lifeforms (bipedalism, intelligence, affinity for climbing) but still weak enough to not completely steamroll over the breeding stock or Predator Trainees within a day (Using their own Predators would be dangerous, since your average Predator can take down elephants with their bare hands, imagine that power added to that of an armored Veloceraptor, along with AVP: Requiem shows that Predaliens are very powerful.). Effectively, we are the plastic of Alien breeding options.

The Predators chose Humans as the host for their Aliens becaue we're the second baddest mofos out there
We've already seen a human beat a Predator one on one before, we can presume that humans have occasionally beaten Predators in the past. This has caused them to have a deep respect for humans as hunters. That is why they choose humans as the hosts as opposed to just choosing a planet full of cattle or dogs. Their are two advantages: 1. The extra sport of facing humans as well as aliens 2. If the candidates do fail the trials the humans have a reasonable chance of confining the aliens in time for the Predators to nuke the place before the planet is overwhelmed.

The Space Jockeys created the xenomorphs to fight a war against the Predators.
However, they ultimately lost, possibly due to the xenomorphs themselves. Afer the war, the Predators saw what excelent killing machines the xenos were and decided to breed and hunt them.

The Aliens have three possible adult forms
1)Queen (as seen in Aliens, Resurection and AvP) 2)Ordinary Adult (as seen in every movie after the first) 3)Fertile Adult (as seen in Alien) There are, however, only two types of embryo chestburster carried by the facehuggers. In areas where a facehugger implants a host with a non-Queen embryo but without a Queen the chestburster goes through an alternate growth period to the typical one, growing a stinger and vemon sacks. The stinger is used to deliver the venom which transforms the vicitms into eggs over time, if the victim is male the egg carries another ordinary chestburster embryo, if the victim is female the embryo is that of a Queen. The production of the venom is very taxing on the Alien, killing it more with each batch it's body creates, which is why the Alien grabbed Bret and Dallas, to ensure there'd be a backup if it didn't survive long enough to create a Queen. Once it had them as back up it focussed on Lambert, only attacking Parker when he tried to interfere. Lambert did end up getting 'raped' but it was just the Alien stinging her. When lambert died the Alien then goes after Ripley, it's last chance to create a Queen, which leads to my next WMG:

The Alien didn't kill Lambert
She had a heart attack and died. Up until that encounter the Alien hadn't actually killed anyone, only cacooning them and turned them into eggs, so why would it kill Lambert for no reason? Lambert likely did end up violated by the Alien in some way but not in a fatal way.
 * The cocooning is only in the director's cut, not the original release. (and Jossed (YMMV) by Aliens)
 * And as the Director's Cut has been released intact, officially, it may very well be canon now. Plus, the alien in the first movie was somewhat different than the ones we see later (most notibly it had a stinger on it's tail) so perhaps this is how aliens that ar born witout a Queen reproduce. See the above WMG for more on that guess.
 * Well it did just brutally kill Parker seconds before advancing on Lambert.

The Aliens give off some weird pheromone/supernatural aura/whatever that causes intense greed in certain people
Almost every time people encounter the xenomorphs, some person decides that, not only is there a potential profit to be made from them, but that the potential profit is worth killing their fellow humans for, despite how that affects their chances for survival. Not only that, but it also tends to push certain people to ignore the social mentality in humans and look out only for themselves.

Alien, Blade Runner, Predator and Avatar take place in the same Universe.
The nature of the synthetics, the attitude of humans towards anything nonhuman (and the mutually returned hostility) makes for a thread that crosses each of these settings with disturbingly similar themes.
 * I like this one! It makes perfect sense:
 * First there was a crapsack world dominated by megacorps (Blade Runner), Predators were probably turned off by this.
 * About a century later said megacorps are exploring space, mining recklessly and colonizing new worlds 'cause Earth is totally fucked by this time. The Nostromo incident occurs for Weyland-Yutani, and a few decades later the Pandora incident occurs for RDA. Ash, Bishop, etc. are, of course, even more advanced replicants. Trudy is obviously Vazquez's little sister.
 * There is aproblem with that: In the Avatarverse, there is no FTL travel (yet?), whereas in Alien, ships can reach about 50 c. So Alien must take place decades, if not centuries after Avatar.
 * Weyland keeps insisting with the xenomorphs (Aliens and Alien3) because RDA was owned by the Na'vi and are offering a ton of money for some new weapon.
 * save for aesthetic differences between the movies, this actually makes quite a bit of sense
 * imagine the Predators wandering around the Blade Runner Los Angeles, I think I just came
 * It's not hard to imagine the hellish LA of Predator 2 eventually becoming the dystopia seen in Blade Runner

Skynet engineered the Xenomorphs and Predators
This may seem a bit wasky, but bear with me. Both the Predator and the Alien share a mixture of human, insect, and reptilian traits. Skynet built a spaceship capable of faster-than-light travel (using a slightly modified time machine) to seed the Galaxy with Artificial intelligence. The ship contained raw genetic material and blueprints needed to make both species, but each serves a specific purpose; The Predators were intended to build another Skynet, and the Aliens were intended to provide incentive to do so. However, Solar wind damaged the ship's CPU and caused it to land on the Space Jockey homeworld circa 1024 AD. The Space Jockeys were at a 21st century level of technological advancement, and the crashed ship accelerated their advancement. However, the actual time machine itself was wrecked to the point that reverse-engineering would be fruitless. The Genetic material for the Aliens and Predators survived, and the Space Jockeys used them as tools of war, both of which rebelled against their creators.

Both the Alien and Predator are symbols of masculinity.
The Xenomorph is obviously a Freudian symbol of masculinity, representing subconscious male urges, such as the desire for sex and food. The Xenomorph is a personification of a man's Id.

The Predator is harder to explain, but could be summed up as the superego. (Someone please help me with this one.)
 * The Aliens represent the primal survival instincts (hunger, defend the children, need to reproduce) while the Predators are the desires (greed, pride, arrogance). So basically Aliens vs Predators is the battle between higher and base human natures.

Aliens are straw feminine symbols while Predators are straw masculine symbols.
Aliens stay close to base (stay at home), have babies, and the movies repeatedly emphasize their blood (this emphasis is recurring, if you will). Predators go out and hunt (bring home the bacon), impale things with their mighty spears, and spend most of their time playing with their fancy, over-engineered toys. The Xenomorphs are also much more smoothly designed, while the Predators are built for blunt utility rather than being as lithe as their counterparts. There are a few things that show the blending of gender by using criss-crossed sexual imagery, such as the Aliens' penis-skulls (their tails from the original concept art were either removed or toned down) and the Predators' vagina-faces.

Aliens are Straw Masculine symbols, Predators are Straw Feminist symbols.
Predators are tough, agile, and clever, and one of the most important facts humans know about them is if they "bleed", you can kill them. They rely on training and reason to defeat their foes, and of course you can't forget that face. Aliens, meanwhile, are one enormous phallic symbol from tail to head, or "glans" if you prefer, using their sheer power and feral instincts to overpower and outflank any foe. Their chief weapon, aside from their caustic body fluids is their ability, and desire, to impregnate absolutely anything they encounter.

Rule 34 is involved with this somehow...
I just know it. There's something in here.
 * Alien's head, Predator's mouth. Done.

Jonesy the cat led the xenomorph to its victims.
Think about it. The cat was present at more than one of the deaths in the film. One could even say it was the catalyst.
 * Ripley wised-up to this: hence she caged it by the end of the movie.

== The destruction of The Nostromo and death of its crew was actually an insurance fraud scheme perpetrated by the company and the Xenomorphs were simply the excuse to be used when/if the there was any investigation == All of the elements of a complex fraud: 1) Replacing the science officer w/ someone that they knew would whatever they were told 2)Using the response to an emergency message as reason to drop out hyperspace and explore the planet 3) Putting a single lifeboat on a ship that could have easily accommodated more. (they may have planned on the crew killing one another just for a spot on it. 4)Not worrying about a lost spacecraft for 57 years and yet complaining about what happened to it when its sole surviving crew member is found and relates what happened. The company never thought anybody would survive, claimed whatever insurance they could and was highly perturbed when Ripley was found alive.

Weyland-Yutani was created as a result of the events surrounding the AvP movies.
Weyland Industries discovered the pyramid created by the Predator aliens. In the sequel, a gun from a Predator was given to a Ms. Yutani.

In the 2005 AvP game, the current owner of Weyland Industries (after Charles Bishop Weyland's disappearance) and a Japanese man (presumably the CEO of Yutani Corporation and father of Ms. Yutani) joined their companies together. The reason for this joint venture is to compare notes to the extraterrestrials. This become their primary (if not secret) goal, and will do whatever it takes to accomplish this (even at the expensive of the consumers). This leads to the first Alien movie.
 * ...no, it leads to Prometheus.

Michael Bishop from Alien³ is a descendant of Charles Bishop Weyland.

 * Many of his ancestors have been working at Weyland-Yutani for a long time.

The little girl in Alien vs Predator: Requiem is the ancestor of...

 * Ripley. Her mother looks a lot like her.
 * Newt. Her last line "Are the monsters gone, mommy?"
 * Both Ripley and Newt. Unbeknowest to either of them, they're actually distant relatives.

Pvt. "Game over, man!" Hudson is a descendant of Jerry Lambert from Predator 2.
They're both played by Bill Paxton.

Prometheus is set in the Alien universe.
The movie started out as an Alien prequel and just because it doesn't have 'Alien' in its title doesn't mean it has to be completely unrelated to Alien.
 * Given the appearance of Space Jockeys in promotional materials for Prometheus, this would seem to be confirmed.

It really doesn't take all that long for a facehugger to implant a host
Facehuggers have one purpose in life, implanting hosts, so naturally they would do so in the manner that provided the highest chance for success. Thus, when one catches a host it latches on and makes the host utterly at it's mercy. This deters other nearby creatures from trying to remove it. It then waits for the host to be left alone and then implants the chestburster within the host, which grows quickly and chews free soon after. It does this because it dies after implantation so it wants the chestburster protected when it's 'born' and still vulnerable.

Ripley's daughter had a child.
DVD releases of Aliens restore a scene cut from the theatrical version, where Burke tells Ripley that her daughter, Amanda, has grown old and died during the 57 years Ripley was in cryosleep. Apparently Amanda married, as her surname is now McLaren, but Burke says she died with 'no children mentioned'. However, we know that Amanda was married, so it's quite plausible that she had a child and gave it up for adoption, which would explain the 'no children mentioned'. Perhaps Amanda was scarred by her mother's broken promises that she would return in time for her birthday – Amanda was afraid that she would fail as a mother in the same way her own mother failed her, so she gave the child up for adoption.

And what became of the child? Ellen Ripley's forgotten grandson? He was adopted by the Jorden family, who christened him Russ. Little Russ grew up, fell in love, got married, had a daughter, then took his family to join an offworld colony called Hadley's Hope, located on the asteroid LV-246. Then, one day (in another scene restored in the DVD releases of Aliens), Russ was instructed to investigate a nearby derelict ship... and impregnated by a facehugger. Since he was the first human in Hadley's Hope to be impregnated, it can be presumed that the Alien Queen seen later in the film was born from his body.

If this troper's theory is true, and Russ is the son of Amanda, then Newt – Ripley's surrogate daughter – is, in fact, her biological great-granddaughter... and the same thing can be said of the Alien Queen. Xenomorphs always absorb the DNA of their host, so just as the alien in the first film was referred to as Kane's son, the Alien Queen is Russ's daughter... and Newt's half-sister... and Ripley's great-granddaughter.

And if you choose to interpret Alien 3 and Alien Resurrection as canon, you can get even wackier genealogical scenarios. Since the ox/dog xenomorph originates from a facehugger laid by the previous film's queen, it's also descended from Ripley. And ever more bizarrely, according to the Alien 3 novelisation, the Alien Queen in Ripley's body was originally implanted in Newt's. When Newt drowned, the alien embryo crawled out of her mouth and into Ripley's. This means that the queen in Ripley's body is some kind of bastard offspring of Newt, Ripley and the Alien Queen from the previous film, who laid the egg from which the fucehugger that impregnated Newt emerged. By extention, every single xenomorph and hybrid in Alien Resurrection is descended from Ripley and Newt, as they're all the genetically tampered-with offspring of the Alien queen in Ripley's body.

AvP:R is a fictional horror movie set in the modern day, made in the era of the original Alien franchise.
I'm glad to let AvP be part of canon but I will be facehugged before I let this thing into continuity as anything more than a parody.

The Colonial Marines in Aliens were always used primarily as a method of ridding colonies of troublesome wildlife.
That's why Hudson asked in a bored tone if the deployment to LV426 was going to be a stand-up fight (with humans) or another bug hunt. Gormon responds that a "xenomorph" may be involved. Some of the marines may not have heard that word before, but they know it means they're in for another boring bug hunt. That's why earlier, during the locker room scene, nobody was impressed when it was said that Ripley was brought along because "she saw an alien once." It may also explain the disdain the marines showed for the "dumbass colonists" in the mess hall scene.

On a side note, I do like the Starship Troopers reference.


 * Does this put Predator, Aliens, Species, and Starship Troopers into the same universe? How awesome of a crossover would that be?

This entire films is just a futuristic retelling of a slave ship revolt story.
Look at this....you have a handful of white people, with their black helper, kidnap an alien and bring it aboard. When it misbehaves they try to kill it again and again with what they have available. The ship is enormous and is designed to carry "cargo." Eventually the "alien" succeeds in getting revenge on his kidnappers and even tries to escape back with the lone survivor only to be cast away into space.
 * It helps that the alien is black.

The Xenomorphs are one of many, many aliens that exist in this universe.
The predators are already acknowledged to exist, as is the space jockey and the xenomorphs. The colonial marines are aware, obviously, of other species. It happens that in this universe, humankind is a bit of a dick and enslaves whatever they come in contact with if possible, or subjugates it for either food, or labor.
 * Mother(the computer) didn't have a directive to smuggle that single xenomorph back. The crew was kept in stasis whenever it came across ANY life or tech the computer determined would be useful and could/should be harvested.
 * "The company" has an interest in grabbing alien technology, established in Av P 2. Plus they have knowledge that there are other, more advanced species out there.
 * Note that the colonial marine weaponry is extreme overkill to put down a human. They had experience by the time of the second film with enough hostile life to come rather well prepared. Put one of those pulse rifles against a plasma caster and see what happens.
 * Humankind may not have FTL travel but that doesn't mean the other species don't. It's concievable that the reason that the humans want the xenomorphs so bad after all these lousy experiences is that they want a bargaining chip of some kind to get FTL drive from one of the other species(space jockeys?)
 * The humans don't want the xenomorphs to be weaponized, they want them as the basis for their own bioengineering capabilities. By Alien resurrection they have super-Ripley which is almost as good as a xenomorph, and is easier to control. The xenomorphs are just the jumping off point to the human program.
 * There's an off-camera war going on and the humans are aware of it but would be powerless against either side.
 * Explains the seemingly futile efforts to harness the xenomorphs.
 * The cyborgs and weaponry keeps getting better and better, not to mention the scale of the military research involved.
 * Could also explain the reson that there is so much research in making a new Ripley to prove that a better, stronger human soldier could be made.
 * One race is the Artcurians. Boy I'd love to get me some of that poontang, male or female!

Prometheus is still a prequel to Alien
They are simply keeping it a secret until the movie comes out. At some point near the end of the movie, one of the crew members of "Prometheus" will be attacked by a Facehugger, but we won't be shown the scene. At the end of the movie, the person implanted will suddenly die, and a person from Weyland-Yutani, or Weyland himself, will see the Chestburster. This will lay out the future expedition to find a Xenomorph egg in Alien.

Alien inherit the Law of conservation from their human "parent".
When on their own as seen in Alien and Alien 3, Xenomorphs can do Alot of damage. In Aliens, when in large numbers they're barely effective. I theorize that this is because once an Xeno is on its own it is using the [[Humans Are Special very human mindset of "survival at any cost." That's when they're at their smartest and that's when they are at their deadliest. In large numbers or when near the hive/Queen. They tend to suck. This along with other traits that their host had I believe are directly inherited.

The Xenomorph is the chest burster/pharyngeal jaw mouth, and it can convert anything to biomass.
The 'mini mouth' has not changed from when it bursts out of a human chest. Once it's grown enough, though, it can create its own support body merely by absorbing the materials around it, natural or manufactured. Being an evolutionary creature, it has an optimised idea of a hunting body, and that body is Giger's alien. But no two accumulations of biomass can be the same, which is why the aliens tend to look different. The reason that the Xenomorphs blend so damn well into the derelict/Colony walls is that its body is composed of it. If you look at Giger's design, the creature looks like it's just an appendage of the background.