The Killing Pit is a wooden trap used for defense purposes.
Killing pits are weight-sensitive traps that are covered with lots of spikes. When an enemy unit steps on it, it triggers the trap and the spikes spring, causing heavy damage to the soldier. Light and semi-armored units die in one hit to them, while units wearing metal armour can withstand several of them. Killing pits are camouflaged and invisible for enemy units, while friendly units can walk over them without danger. After a pit is triggered, it vanishes after some time and cannot be used again.
In Stronghold 2 and onwards, the man trap is used for single-target traps. The killing pit however, is rather effective against mass units and troops wearing heavy armour. It covers a larger 2x2 area and is more expensive, but units falling in the pit die instantly. The pit instantly opens when a single knight steps on it, but it does not trigger under siege engines and few light units. Killing pits placed in front of a wall section will always trigger when a ladderman attempts to set up a ladder. Activated pits are removed instantly.