Alien

Xenomorph

Facehugger

A parasitic cycle in xenomorph production with the appearance of two human hands held together and attached to a spiny, powerful tail. It has a proboscis it uses to implant embryos and provide oxygen while strangling a victim. The finger-like appendages are used for transportation and to attach itself firmly to a host body. Once implantation is complete, the facehugger falls off and dies. Removal of a facehugger while it is copulating is always fatal for the victim, either because of a snapped neck, trauma from the facehugger ripping off the face of its victim, or the powerfully acidic blood of the xeno. Victims rarely remember implantation or even the act of being jumped in most cases, likely because of the asphyxiation caused by a facehugger's tail during the process and the psychological trauma of the act. Like all of the xenomorph species, not much is understood about its growth, motivations, or senses, but it is known that a facehugger can tell the difference between a living humanoid and a non-living humanoid such as corpses or cyborgs and that they are suicidally focused on reproduction. Xenomorphs often use crowds of facehuggers to take down large prey or grouped or well-defended humans.

Larva

See? What did I tell you?

Also known as chestbursters because of their method of exodus from the host body, larval xenomorphs are the third known stage in reproduction for that species. While developing in the body, xenomorph embryos attach to blood vessels to absorb nutrients and complete its unstable genetic structure using the host's DNA. Through an unknown process, this always results in a functioning offspring. This form is small compared to the adult, limbless, and serpentine. They have a strong instinct to hide after forcing their way out through the ribcage and violently tearing their host body apart. If left alone, xenomorph larva will undergo an unknown transformation process to adulthood. It is believed at this stage that the xenomorph is at its most vulnerable due to its small size and apparent lack of many senses, though this should not be misunderstood -- a larva is still deadly. Its powerful thrashing and sharp teeth got it out of a human sternum, after all.

Hunter

Now everyone is dead.

This form is usually the last in any given xenomorph's life cycle. There are many variants of the hunter (including forms that do no hunting, per se), but the human form is the most commonly seen on stations for obvious reasons. The hunter sports a phallic-shaped skull with hidden, mostly useless eyes protected by a one-way transparent dome. It has a host of esoteric senses, most prominently a theorized echolocation (explaining their near-constant hissing) and electroreception, though its primary sense appears to be smell. The scent of pheromones is experimentally shown to be the primary communication device of xenomorphs, most effectively transmitted by the ropey purple weeds the adults spread around the station. It is unknown where this tissue comes from, as xenomorphs refuse to make it in captivity. The primary byproduct of this weed is the strange substance plasma and as such most corporations are extremely interested in the connection between the xenomorphs and that chemical for production reasons. Like the facehugger, the hunter's blood is highly acidic, and there are rumors that it is capable of eating even through space station hulls, though it must be said that this is only a rumor.

The adult xenomorph is a living weapon, with an exoskeleton thick enough to absorb or redirect most trauma and temperature extremes, scythe-like claws, and a multi-tiered jaw system capable of projecting an acidic compound presumingly from their stomachs. Some varieties of hunter are crested, and most varieties have a heavy tail with protective ridges. Xenomorphs at this stage show semi-sapience and problem-solving abilities, and are capable of using pack-oriented tactics, creative stealth, and psychological manipulation. It is reported that in the presence of enough plasma xenomorphs can communicate in a basic way with sentient species, but there is little evidence to lend credence to such an absurd notion.

Queen

Nuke the station out of orbit. It's the only way to be sure.

Very few xenomorphs undergo the transformation into queen. It appears to be done only in the case of very specific hive pressures. They are the only xenomorphs capable of laying the eggs that hatch facehuggers. While much larger than the hunters, they're also much slower, but are indeed much tougher. Even accounting for the size difference, a xenomorph queen can take drastically more punishment. A queen is most likely found where there are high levels of plasma, surrounded by hunters and swarms of freshly hatched facehuggers. They are significantly more intelligent and highly protective of their offspring. While slow, they have all the adaptations and weapons of their previous hunter forms, a larger, thicker crest to protect their brain casing, and higher internal stores of plasma which they can utilize for the shaping of resin, the laying of eggs, destructive survival defenses, and even a complex and poorly understood efficient means to form a natural cloak. Like all xenomorphs, there is little information about them.

How to Play

A lot of people like aliens, either playing as, fighting against, or being stroked by them. Fortunately for those of us who do, random alien events and/or answered prayers tend to happen very frequently. Unfortunately, however, it seems a lot of people have no fucking clue what they're doing when they spawn as one. This is a guide describing some basics and tips about playing as a xeno so you're not stuck in ooc going "how does I play alium?"

This guide is fairly comprehensive and long. There is no tl;dr for this shit, so tough it out, soldier.

Prologue

Aliens arrive on the station in one of two ways. The first way is for the random event where CentCom broadcasts that an Unidentified Lifesign has been detected aboard the station. This means that in a very few random places around the station, facehuggers and eggs have been seeded. They can pop up almost anywhere, even right next to you (if this happens you are pretty much stuck being faceraped). The second way is for admins to spawn them. This can either be as a forced random event (I think) that is exactly like the CentCom alert, OR they could just hide some facehuggers and/or eggs somewhere on the station while they cackle evilly to themselves waiting for some poor unsuspecting assistant to get a very slimy face full of alien wing wang.

"Shit, my face has been raped by xenos." Currently, being facehugged is not a guarantee of infestation. There is at least a small chance that you will not shortly explode, your guts sprayed across the cold metal floor plating of the station, as a new larvae is born. Good luck with that.

If you've been infected, there will usually be telltale signs. You'll feel sick. Your throat will be sore. You'll cough a lot. These symptoms mean you are forming a babby. You can seek medical attention, which you are pretty much guaranteed not to receive in a timely fashion, whilst people dick around trying to get you into the cloning machine to scan you before you gib, or maybe you'll be lucky and your brain will be torn from your body so you can become a MAN OF STEEL. The staff might also just kill you outright to keep the infection from spreading. Who knows.

If someone helps you, great. If you don't WANT help, perhaps exploding into a bloody mess as a glistening black monstrosity is born is your fetish, or maybe you've just grown to hate everyone on the station for being the fucktards that they are, you can do a few things to help ensure that your new little baby alien can grow up safe and happy.

The best thing to do is be by an un-welded air vent where nobody is looking. The second best thing to do is to find an unpopulated, limited access part of the station like Engineering or Atmospherics where nobody will ever go unless they have to.

If you want to be extra cautious, disable nearby cameras. The AI won't spot your special delivery until weeds are covering the station.

From a metagame perspective, it's optimal for you to ensure the ongoing life of the alien larvae, as you are pretty much guaranteed to die. If he survives to raise a brood, you have a better chance of rejoining the game as a newborn larvae than you ever did trying to get the staff to scan you for a clone.

However, metagaming is frowned upon, so for the love of god, if you're going to do it, be discreet. Because it's not direct griefing nobody is going to really care, especially since there are usually a lot of murdered people who would love to be reborn as xenos so they can get their revenge.

So, you want to play an alium?

Phase One

Oh shit I'm a larva what do I do?

You've just spawned and are weak as shit.
Above the chat window is your status window. It has index tabs. Click the Alien tab. It shows you all your magical alien powers.
As a larva you cannot attack and you have no special alien powers aside from Crawl Through Vents.

If there's anyone around when you burst, you may be fucked. Turn on Yakety Sax and run for your life. Finding a vent is your best, and probably only chance of survival.

If you're not in a good spot, find the nearest vent and for the love of god crawl through it.
A good spot is anywhere where you A) are not likely to be found and B) have an easy-access vent. If it's dark, that's even better, since someone who comes inside may not see you unless they get close.

You can spam crawl through vents faster than anyone is going to react to your presence, so don't be afraid to scout out as many locations as you can to figure out the best place to hide.

If for any reason your hiding place is found out, don't be afraid to crawl through dem vents and find a new place.
If you're stuck in a room with no vents, and doors you can't open, just tough it out. Hopefully nobody knows you're there.
Once you're in your spot, sit and wait to evolve.

Phase Two

Fuck yes, I'm a xeno, time to go kill some motherfuckers.

STOP RIGHT THERE, CRIMINAL SCUM, don't run off to kill people just yet. Or ever.
Revealing yourself now is the dumbest possible thing you can do. Seriously, what were you thinking?
As an alien, killing someone is something you never want to do. Ever. Killing them means you can't get them infested, and that's absolutely retarded. What kind of alien are you?
As an adult alien you have a lot of new alien powers. They do stuff. The most important one right now is Plant Weeds.
Aliums run on plasma. Your body stores plasma and your magical powers need it to work. You can absorb plasma two ways: plasma in the air and weeds. Yes, they can stack.
If you don't plant weeds, you won't build plasma, so plant those weeds and store some up. If you waste your plasma before you plant weeds you are fucked unless plasma is in the air, and even then you absorb far more plasma over time from weeds.
Great, you're building plasma. Now comes decision time: Do you want to evolve into a queen or be a marauding hunter?
If you are the first (or one of the first) aliens, you should evolve into a queen. Without a queen, there is no way to spawn additional facehuggers, and no way to expand the brood. Aliens are not a threat without facehuggers, so queens are a must-have.
If there's already a queen, you can choose to stay as a regular adult and fuck some shit up. There are good reasons to do this. Queens move slow and cannot vent crawl, so having hunter aliens makes collecting new hosts much easier.
For the sake of this guide we will assume you are one of the first aliens, but if you join as an alien partway into the infestation of the station you can skip to the final phase.
Since you probably want to become a queen, your best bet is to just sit tight and build up 500 plasma to evolve. The sooner, the better.
The crew is probably looking for you at this point, so make sure you're in a relatively safe spot. *Once you evolve you are very slow and won't be able to vent crawl. You will be very vulnerable until you build up an army of facehuggers, so plan your nesting ground accordingly.
If for any reason you know that the genetics lab or toxin lab are no longer being used and the monkeys are still alive FOR THE LOVE OF GOD, nest there.
During this time you can continue to scout around through various vents and see where people on the station are.
Jumping through vents and planting additional weeds in random places is a great way to divert attention from wherever your actual nest is. The crew will flip their lid at the sight of weeds, so it's often worth it even though it does slow your progression to queen.
Now it's time to play the waiting game again. 500 plasma and it's on to phase three.

Phase Three

I'm a queen, but how is babby formed?

Let's get this out of the way, first: You can caress anyone with your scythe-like arm by clicking on them with and empty hand, with the Help intent active, while they're next to you. This is no help to you or anyone else. Moving on.
You're a queen. Awesome. You get some nifty bonuses and defects compared to regular aliens. Let's go over them.
Cons: You are slow. And by that I mean fucking slow. Snail's pace. You also can't vent crawl. Oh yeah, and your attack power sucks. You basically have zero mobility compared to everything else in the game. You also stand out. You basically suck balls.
Pros: You can lay eggs, you build plasma four times faster than regular aliens (20 units per tick as opposed to the normal 5), and you have more health. Also some people will think you're sexy. You basically kick ass.
One other special thing you can do is once holding someone by the neck you can devour them whole by dragging their sprite onto yours, regardless of their condition. They will stay inside your stomach until digested. This is usually not helpful as you should instead infect them for more alien help, and eating live humans can lead to severe terminal indigestion.
Your first task is to lay an egg. You start with 250 plasma even though you needed 500 to evolve, and you'll build more very quickly.
If at any point in time you have plasma built up and don't know what to do with it, lay another egg. Laying more eggs increases the facehugger swarm and is your best weapon against the humans.
You can open any door that isn't ID locked, but locked and/or bolted doors require that you spit corrosive acid on them. Corrosive acid is your all-access pass to the station. If you're stuck for any reason, or want to get in somewhere (example, rooms with monkeys or plasma tanks), use dat acid. It takes a while to eat through doors usually, so spit early and lay eggs while you wait.
Remember how I said you're weak as shit? It's true. Alone, aliens are wimpy, and a queen even more so. One lucky assistant with a toolbox to the head can end your infestation very quickly, so don't let it happen. Always lay low and keep a wall of eggs and facehuggers between you and anywhere humans can get at you from.
If you are spotted, use the alien power Invisibility (50). This is not the Wizard's invisibility, it's a temporary syndicate-style cloak. It's always a good idea to not drop yourself below 50 energy so that in an emergency you can always have a chance to hide, or buy time while you get ready to spam some spit.
If you for any reason need to defend yourself, RIGHT-CLICK > SPIT (25) (or clicking the spit verb in your alien tab) is your godmode. Don't bother trying to melee people, that's only if you like dying. This also applies to regular adult aliens. Spit spam is fucking ridiculous. It's cheap to cast and acts like the Wizard's magic missile, including the homing and meager damage.
When you incapacitate someone for any reason (probably by stunning them with spit), stroll on over and strip off all their possessions. Start with dangerous things like radios, weapons, air tanks, and backpacks. ALWAYS take off the radio first. If they call in your position and you don't have enough facehuggers, you are fuuuuuucked.
Drag anyone you incapacitate back towards the heart of your hive. Make sure that when they get back up, a facehugger will be within jumping range. The alien wing wang is your best and final weapon. Once they're impregnated, feel free to drag them to some dark corner and caress them while you emote sultry things until they explode into a new alien baby.
Remember what I said earlier about monkeys? Monkeys and the humans they've probably been turned into are viable facehugger targets, and are a fantastic way to rapidly expand the size of your brood without needing to hunt down those pesky oxygen tank-wielding humans. From a meta standpoint, they also let more players into the game without killing anyone, so it gets more ghosts back to playing, which is always good. Same goes for AFK people.
Once you've amassed an army of facehuggers, and hopefully ambushed a couple unsuspecting crew who were unfortunate enough to stumble on your nest, you should communicate closely with the other aliens and prepare to start really branching out across the station. You've already started this, probably, especially since the other alien players are probably being more aggressive than you.

General Advice

You do not need air to breathe as a xenomorph! Feel free to walk around the outside of the station and make a good safe area to plant weeds and store plasma on (i.e., the solars, or toxins test area is no one is bombing or has bombed it). You can also spit acid on windows/grilled to destroy them, so any window is a potential entry point. If you get spaced you're usually out of luck, though!

The atmospherics vent leads to a safe 3x3 room with a single cannister inside it. Go here if you really have nowhere else to go, as it's 99% safe. Only bombs can get you there and even the AI can't see that room.

Don't go into space without ripping a lamp or lightbulb out of it's socket. Not only does this give you a tactical advantage later, you can throw those if you slip into space or (more likely) a facehugger jumps like an eager puppy in front of you and gets you stuck in space.

Rip out lights and smash them against walls! You can see further in the dark then humans, and facehuggers have even better vision. Humans, without flashlights, can only see one tile ahead. Break all those lights and humans will become afraid of entering the dark areas, with good reason. This goes double for a queen, since the queen can't really fight worth anything and relies on the facehuggers and other xenos to protect her.

If someone dies before they give birth to a glorious new youngling, drag them to genetics/medbay if you can do so without being killed. If they're alive, they're ready for another facehugger. If they suicide by the suicide command just to stop a chestburster (which you shouldnt do guys, I'm being serious, the ghosts want a chance to play again) get a queen to eat them so they can't be cloned either.

Totally eat people if your life is in danger, and you need health (don't eat everyone, you need xeno babies to be born). NOTHING CAN POSSIBLY GO WRONG (except reverse chestbursting, but that hardly ever happens)

You can also pick up anything medium sized or larger, such as boxes and backpacks. This means if someone somehow leaves an energy sword on the ground, in the 'on' mode (this makes it a bulky item), then there will be sword wielding aliens. In general you can better use this to just pick up backpacks and throw them for movement in space. (Please note that backpacks make very poor weapons.)

How to Defeat

PAY YOUR DUE

Oh shit it told us to weld the vents what now?!

Calm the fuck down. Are you a human being or a groxian hyper-coward? The former is the proper response.
Have you welded the vents yet? It's good advice.
Make sure a hive is never set up. Use suicide vests, flamethrowers, energy guns, and the secret monkey technique to destroy facehuggers and alien weeds so that an infestation never finds a foothold. Note: THROWING THINGS AT FACEHUGGERS JUST MAKES THEM ANGRY.
Kill your friends for fun and profit! They can just be cloned or borged, but if they've got a bun in the oven, it's already too late for them. Kill them before they kill themselves and everyone else on the station.
Amy Lessen, stop that! Certain crew members may seek to make peaceful contact with the aliens, or may actively seek to become infected. Take precautions to ensure the crew know the dangers of consorting with the xeno menace.

But we're all hopelessly stupid and incompetent. The aliens are everywhere! What now?

Shoot everything that isn't person shaped.
Shoot everything that's person shaped but helping the xenomorphs.
Shoot the monkeys too, just to be safe. CentCom will send us more.
Keep a transparent barrier between you and the xenos at all times. Use flashbangs and other detainment devices to keep them at bay. Remember that their spit is acidic and paralytic! They will use it to ruin you.
Stay close!
If you see a larva, chase it.
Seriously consider calling the shuttle.

Everyone is dead but me! What do?

If you have weapons, use all of them. Even if you don't think something is there, shoot the empty hall anyway! Aliens can turn invisible! They're behind you right now I guarantee it!
You may think that since they can turn invisible, xenomorphs are like ninja. You may think that if you light yourself on fire they won't be able to catch you. You are wrong. Xenomorphs love being on fire or frozen, it is as common a fetish in their species as fucking that which should go unfucked is in our own. You are only attracting them to you, in many disturbing levels.
If the shuttle is here, get on it, weld the doors shut, make sure nothing is in there with you, and hide as best you can. Central Command has a plan for this sort of thing. They'll save you and your little cat too.
If you are eaten alive by xenos THIS IS A GOOD THING. Take out your oxygen bottle or any other weapon in your hand, and TRY MOVE AROUND LIKE A FURIOUS BABY WITH FAMILICIDE IN MIND. You'll slam the thing you're holding into the alien's stomach lining, and if you do it enough you'll EXPLODE out of the aliens chest cavity like some kind of reverse-larvae. CAN YOU TAKE WHAT YOU DEAL OUT, XENOS?!
If the shuttle isn't coming, write a book of warning and contempt and throw yourself into space. If you're too much of a coward to do it the glorious way, bash yourself unconscious and wait to be eaten.