Hello, let's talk about "Zoe", our real foe in game.
1 Based from v2.5 infos (UFOpaedia), we may infer that:
- Zoe's intelligence and battle awareness depends on its size. A size of 10 roughly correspond to a human intelligence.
- When Zoe is held inside a PHALANX base, it's alone, and not very smart.
- A small zoe doesn't seem to know other zoes may exist. It exists and that's all.
- Small UFO have no apparent communication systems, and aren't meant to land on Earth.
- Alien Bases contain a device called a Psi Amp for a purpose.
- Zoe seems to be able to partly use past memories when it focuses on a host; on the other hand, a non focused on host looks like zombified.
- Likewise, a formerly member of Zoe may be left into a helpless state (catatonic), especially if it spent all its life inside Zoe, as guessed by Doc. Connor.
2 Now, we have a few inconsistencies, AFAIK:
- How the small crew of a small crashed UFO manage to oppose coordinated resistance to PHALANX S&D teams whereas the same amount of aliens stay passive when prisoner?
- How the large crew of an alien base or a large, landed UFO may suffer morale checks whereas a Psi Amp could (presumably) link them to a greater Zoe? To a very large Zoe, one killed member should count for naught.
3 Extrapolating a little:
Zoe's smartness and awareness grows logarithmically with its number. We can use different AI levels to represent this.
Depending on the number, AI level would be:
1: animal -> catatonic state, self-defense if threatened (mostly returning fire and throwing things), non-coordinated moves.
2-3: beasty/child -> catatonic/berserk behavior, self-defense if a potential threat is detected, coordinated moves.
4-10: sub-human -> possible morale effect, coordinated moves, simple task handled in team (kill, gather, defend).
11-30: human-like -> no morale effect, coordinated tactics (e.g. go to target location), use of any weapons at hand.
31-100:super-human -> more AI "cheating" as currently: more TU? Improved reaction fire? See-through or short range detection, etc.
A single Alien which is separated from Zoe is left in a "childish", catatonic state of awareness and smartness, because all its life was within Zoe and it doesn't have any personnal memories and experience.
A separated Human should not be left in such of zombi state, rather returning to its pre-Zoe life, and loosing any memories and experience while inside Zoe. That would help detecting infiltrated Humans if a severing mechanism may be found. Infected Humans are still detected through XIV test.
4 Zoe's extension in space:
Generally speaking, the largest Zoe is, the longer distance one of its members can go without leaving it.
However, there's a distance where the link between Zoe and the member is lost. The member becomes helpless (AI level = 1), and may be assimilated by any other zoe it may cross the way.
Mighty Zoe has devised com-links between spacecrafts that enable much larger distance between members (crafts).
Also, the Psi-Amp found in Alien Bases on Earth enable the base to be linked to some orbital or extra-orbital relay, and to hold a grasp onto any members on Earth, a few hundred kilometers around.
5 Division and assimilation(growth):
Zoe is able to lose parts of it, and to grow by assimilating (intelligent) life forms. In order to be assimilated into Zoe, a life form must first be infected by Zoe or by a cousin (former part of it).
Life forms into Zoe may be controlled quite well if Zoe is large. Their brain is used more efficiently than Nature does. A large Zoe knows how to use its members most efficiently, using the nimble for agile tasks, the strong for demanding tasks, the smart as computers and memory banks.
Indeed, a Taman could count as 2 Shevaars/Ortnoks/Humans to estimate Zoe's strength.
When Zoe loses members, it virtually loses only strength, so that the loss may be neglectible. An exception is when the lost members had been severed from Zoe for a while, and thus didn't had time to be re-assimilated and to share any new data they might have collected in the meanwhile.
Even so, it's doubtful that any Zoe would engage SAR missions to retrieve the surviving crew of a crashed UFO. They are quite worthless.
Division procedure:
Division of Zoe in two parts may occur either voluntary or involuntary.
Involuntary division happens when a Psi Amp is neutralized, and a part is isolated from the other (this may happen when an Alien Base is assaulted, or sometimes when a large vessel has crash landed), or the distance between the parts becomes accidentally large (such as when prisonners are brought inside a PHALANX base).
Voluntary division happens when Zoe send a craft or even a squadron on a course that lead them out of its range. It should be the case for any small UFO, and some early or desperate "no-return" assault missions.
Assimilation procedure:
Two zoes can't exist next to each other. As soon as range allows, the largest start assimilating the smallest, and the smallest won't try and defend itself (perhaps, it "knows" what is good for it).
Assimilation depends on the relative strength of both collectivities. The assimilated zoe ceases to exist as an entity as soon as the process is over. The assimilating zoe gains in size, plus all the memories and any experience from the assimilated one.
When powerful enough, Zoe is able to elaborate plans to test the capabilities and usefulness of new life forms (species) and the usefulness of given individuals from a well known species.
It's why, from the mid-game on, Zoe is able to target VIP on Earth and infect them, in hope to assimilate them later on.
6 Zoe and the UFOs:
At the beginning, UFOs are Scouts, Fighters, all crafts without any com systems nor psi links.
The crew is naturally separated from Zoe as it enters the athmospheare (or perhaps, before this happens).
Most of the mission is automated but Zoe in craft is potent enough to conduct routines and to react to new events such as departing from a scheduled course, fighting incoming Terran crafts, etc. It knows what "escort" means as well. Perhaps, there is a kind of briefing mechanism to educate it after the severing.
When mission is fulfilled or otherwise terminated, Zoe "knows" what to do, e.g. actionning a button that engages an automated return flight.
When the craft flies back to greater Zoe, it's re-assimilated and delivers all of its bio- and electronic-data.
We may consider that Supply Ships and Harvester work on the same principle, only that Zoe is large enough to have a kind of autonomy sufficient for the mission's purpose. A Supply Ship is a heavily automated craft anyways, but the crew knows what to do when it lands on a bare patch of land (to found a base).
Crew-size Zoe is able to conduct harvest missions because they are assisted by robotic units, and it's only a matter of killing and retrieving living things (or humans, specifically).
Even an early terror mission may be conducted by a disposable Zoe: the crew is educated to kill as much as possible and to defend itself. The UFO could have a count down mechanism that triggers an automated take-off and return (that never happens in game, save with certain ground missions without UFO?).
Corrupters, Bombers, and even Gunships, on the other hand are valuable and large enough to have kind of a com-link, a special point-to-point psi-amp indeed, that prevents the crew to be separated from greater Zoe. When the UFO lands on Earth, the link still ensures that Zoe is at its full potency (to the demise of any PHALANX team).
However, crashed UFOs have a chance to have the com-link unit destroyed, so that Zoe on Earth is barely more potent than a smaller UFO's crew.
As for the Alien Base, the Psi-Amp room serves not only as a point-to-point, long range link to keep contact with greater Zoe, but as a surface broadcast, medium range link that enable Zoe to control ground forces all around the base (up to several dozens of kilometers or several hundreds?), either Alien teams from the base, or Human XIVs.
During a base attack, PHALANX team is able to disable the Psi-Room device when they occupy the room for several turns (e.g. winning the mission). There is no point to go on fighting the surviving base defenders because, perhaps, PHALANX learned how to use the Psi-Amp to incapacitate nearby small Zoe.
7 Zoe and the Humans:
A Human must be infected before it can be assimilated into Zoe.
Infection takes a few days with a primo-reaction akin to a flux, due to our immunity system.
To keep infected Humans into it, Zoe needs either a nearby landed, linked UFO, or an operationnal Alien base. Of course, other infected Humans may be part of this chain of influence.
Humans focused on by Zoe may behave quite the same as the non infected ones. However, as with the Aliens, whenever Zoe doesn't focus anymore on them, they perform only routine tasks and may look strange to relatives (colleagues, familly, friends).
Zoe is perfectly able to use many members at the same time, but it needs to focus on them for this to happen, a little like sea anemones would violently react at each stimulation, retracting one or several "arms", and would otherwise let their "arms" passively feed from whatever floats in the water.
8 Consequences and suggestions in game:
- Alien Containment: memos and research proposals by Doc Connor, each time a AI level is reached (e.g. at 1, 2, 4, 11... 31?). Currently, there are only 3 stages (?), and beyond 10 prisonners, it isn't worth capturing more Aliens.
- Battle Debriefings: memos by Col. Falkland or the TACOPS, to recall how the Aliens' behaviour changed during the battles when their number shrinks. Also the unexplained difference in the enemy tactics between a landed crew, and a crashed crew from a medium-size UFO.
- UFO Com-link: add in the post-research report that an unknown, yet clearly separated unit is found in the Corrupter, the Gunship , and the Bomber. Perhaps, delaying its understanding (after proper research) until the first Alien Base Psi Amp is retrieved.
- Ground Missions: the game is able to dynamically adjust Alien AI level, depending on the size of surviving Zoe. This allows for finishing maps faster(?).
- Morale effects: Aliens are no subject to morale effects the same way as Humans are. If the smallest zoe would hardly strive to control its hosts and occasionnal morale effects could randomly occur because of this (only with Aliens), greater ones would be impervious to this, and the loss of one or several members shouldn't have any consequences, besides reducing the overall strength, hence the AI level..
Perhaps, a kind of sideration could be achieved when a member is severely wounded (or stunned?): Zoe would briefly (one turn) loose its grasp (contact) and a morale effect could occur as well.
- Alien Mind research: the research tree should be revisited a bit (to compile the overall behaviour of Zoe).
- XIV research: perhaps, Doc. Connor and teammates could devise a mean to temporarily disrupt Zoe inside a Human member (electric+chemical shock?) while still under range of influence, and see what happens. The electrolaser could be used for that purpose.
- Severed Alien crews are more important if mission objectives are more complex. No more terror mission with only two organic aliens and half a dozen of robots. 2 such aliens would be so unuseful, is severed.