Threat (Long War)

The Aliens adjust their strategic operations based on how threatening they perceive XCOM to be. Threat affects how they schedule their UFO sorties & how often they try to ambush XCOM ground forces during UFO landings.

Threat Counter

A running tally of threat is incremented over the course of the month as XCOM successfully launches operations against alien UFOs.

• Shoot down or successfully assault a Scout, Fighter, Raider, Destroyer, or Abductor: +1
• Shoot down or successfully assault a Harvester, Terror Ship, Transport, Battleship, Assault Carrier, or Overseer: +2

This threat counter is used to determine the UFOs fielded in the following month as well as the likelihood that a particular landed UFO will be a Trap UFO in the current month.

At the beginning of each month, after the missions for that month have been determined, the threat counter is normally reset to 0. However, if it was 6-7 at the end of last month, it is set to 1, and if it was 8+ at the end of last month, it is set to 2 instead.

Trap UFOs

The chance of any particular landed UFO being a "Trap" is based on the current threat counter in the moment it lands. Thus, it is significantly lower in the beginning of the month when the counter is close to 0, but much more likely by the end of the month if XCOM has been diligent in shooting down UFOs.

Chance of Trap: Threat Counter / 30

For example, if the current counter is 5, there is a 5/30 (16.67%) chance of a landed UFO being a trap.

Trap UFOs have significantly increased numbers of aliens; generally, the smaller and more unassuming the UFO type, the greater the relative increase. Traps can only occur when UFOs successfully land; UFOs that can't land aren't listed, and UFOs that get shot down will also never be traps. Research missions and Harvest missions can be traps. For more information on each UFO, see the UFOs page.

Every enemy pod on a trapped mission has the Call for Reinforcements ability which normally only a Command Pod gets. Thus, once the shooting starts, all the numerous aliens on the map will be rapidly converging on XCOM's position; a weaker squad can easily find itself overwhelmed.

Landed UFO Troop Counts
UFO Type	Regular	Trap
Scout	10-12	21-24
Raider	17-22	26-38
Abductor	22-29	32-49
Harvester
Transport	34-45	46
Terror Ship

UFO Mission Scheduling

At the end of each month, the current Threat Counter, in conjunction with alien resource levels, determines the types of missions the aliens will field in the next month. In general, the total number of missions is more linked to resources, while threat level determines how aggressive those missions are, with the Aliens tending to target XCOMs satellites and engage in more Terror missions at high threat; see the missions table for details. Note that, for the purposes of mission scheduling, if an Alien Base was raided in the previous month, threat is automatically considered to be at its highest level (8+); this does not affect the likelihood of a UFO being a trap.

Furthermore, when determining the location of a Harvest mission, high threat may cause aliens to try and avoid XCOM's satellite coverage. This is represented by a chance that the aliens will reroll the target country if it has a satellite over it:

Threat	Chance
0-1	0%
2-3	10%
4-5	20%
6-7	30%
8+	40%

This reduces Alien Resources by 5. The reroll algorithm will always pick a random new location without a satellite. If no such location is available (i.e. XCOM has all 16 countries covered by a satellite), the reroll is canceled and no cost is accrued.