Black Hole Factories are buildings that only appear in campaigns, and unlike other buildings, they are 12 tiles in size and cannot be captured by infantry. They make their debut and currently only appearance in Advance Wars 2: Black Hole Rising. They can build any unit given the terrain allows it (e.g. they cannot produce naval units unless there is a sea tile in front of them), and up to three units at a time. They don't use up any war funds and are powered by Black Hole Pipelines. However, destroying the Pipe seam will shut down the factory and end the mission in victory.
Strategy[]
Each Factory has a set pattern of unit deployment. Blocking the entrance of the factories prevents them from producing units. This technique is also used on regular bases, ports, and airports. This leaves your other units free to attack the seam and win the mission.