Alien Infiltration (Apocalypse)
Alien Infiltration occurs when the aliens directly deploy alien life forms into buildings. Aliens will then spread through the organization that owns the building and other buildings next to the original one (thus infiltrating other organizations). If left unchecked it will progress as time goes by. If infiltration reaches 100%, the organization will fall under alien control (becomes allied with the Aliens, becomes hostile to X-COM, gains +3 tech level, and uses the Megapol/gang table for crime actions).
It is possible to see the UFO deploying the aliens on Cityscape Screen when using the Isometric Map View) (it hovers above a building and uses a grey tube, as shown in the image).
This alien tactic can be stopped by shooting down the UFOs or by conducting an early search on the building without waiting for the alien alert. It is better to kill the infiltration right at its source before it can spread to nearby buildings, which will be the case if X-COM chooses to wait until alerts are generated.
The effectiveness and speed of alien infiltration are affected by several factors, including the type of building, the organization owning said building, and the actual aliens which are involved.
Building infiltration potential
| Building | Infiltration Potential |
|---|---|
| People Tube, Road | None |
| Appliances Factory, Arms Factory, Astrodome, Car Factory, Construction Factory, Flyer Factory, Hydro-Farm, Large Flyer Factory, Power Station, Recyclotorium, Rescue Station, Robot Factory, Sewage Works, Slums, Water Purifier, Warehouse | Low |
| Apartments, Hospital, Luxury Apartments, Offices, Police Station, Procreation Park, School, Sensodrome, Shopping Mall, Space Port, Temple of Sirius | Average |
| Corporate HQ | High |
| Senate | Very High |
Organization infiltration speed
| Organization | Infiltration Speed |
|---|---|
| S.E.L.F., X-COM | 0%* |
| Government, Mutant Alliance | 50% |
| Cyberweb, Energen, Evonet, General Metro, Grav Ball League, Lifetree, Marsec, Megapol, Nanotech, Nutrivend, Sanctuary Clinic, Sensovision, Solmine, Superdynamics, Synthemesh, Transtellar | 100% |
| Diablo, Extropians, Osiron, Psyke, Technocrats | 150% |
| Cult of Sirius | 200% |
*These organizations are completely immune to infiltration.
Alien infiltration weight
| Alien | Infiltration Weight |
|---|---|
| Chrysalis, Multiworm Egg | 0 |
| Brainsucker, Hyperworm, Megaspawn*, Multiworm, Popper, Queenspawn* | 1 |
| Anthropod, Micronoid Aggregate*, Skeletoid, Spitter | 2 |
| Psimorph* | 3 |
*These aliens are not normally deployed for infiltration missions.