Fougasse is a pre-battle deployment option in Empire: Total War.
Fougasse is available to some of the less advanced skirmishers, such as Light Infantry. They gain the ability to deploy it before battle if they remain stationary on the campaign map for two or more turns.
Once deployed, Fougasse takes the appearance of a small rectangular box with a large red mark in front of it. Any enemy that wanders onto the red mark causes the explosives stored in the box to detonate, showering the area in front of it with debris and causing casualties. The explosions are lethal and demoralises any foe that steps on them.
Units that may deploy fougasse may only do so when they do not have the Light Infantry Doctrine behavior toggled to on in the pre-deployment phase of the battle.
Some more advanced skirmishers have access to Improved Fougasse, instead.