Dark Events (XCOM2)
Dark Events are activities undertaken by the ADVENT administration to counteract XCOM operations. They will usually undertake 3 per month(2 at the start of the game) and you will have the option of preventing one of them with a Guerilla Operation.
One Dark Event is usually 'hidden;' you can counter(or deal with it) blind, or spend a small amount of Intel to reveal what the aliens are doing against you.
Dark Events are worked on in sequence, though not necessarily the sequence presented in the game. As such, it is possible to sometimes prevent more than one of the listed projects based on how you tackle them.
Most Dark Events last for a month, although some have instant effects once completed.
Known dark events
ADVENT Alloy Padding: Some ADVENT troops get an extra pip of armor. Avatar Minor Breakthrough: 1 block of progress is instantly added to the Avatar project at a random location. Avatar Major Breakthrough: 2 blocks of progress are instantly added to the Avatar project at a random location. Hunt Avenger: A UFO is dispatched to hunt the Avenger; if it finds it, it will trigger Avenger Defense. Infestation: Chryssalids spawn on every mission. Infiltrators: Faceless spawn on every mission. Resistance Mole: Retaliation counter is reduced by two weeks. Alien Construction: Alien Facility Construction counter is reduced by two weeks. Viper Rounds: Some ADVENT troops gain Venom Rounds. ADVENT midnight raids: All recruiting costs doubled. ADVENT rural checkpoints: Next Supply Drop supplies reduced by 50% Alien Cypher: All Intel costs doubled.