Boulder traps are a type of deadfall trap in which a large rock or boulder (or statue, log, or other heavy object) is set to crush unsuspecting intruders when the trap is sprung. These boulders may be positioned to roll down on their victims, swing into them, or fall directly on top of them. They are generally triggered by pressure plate or tripwire. Boulder traps are frequently found in ancient temples, treasure islands, and game dungeons. There may be skeletal remains nearby.