The sentry is a security device used in Jak 3 by the Precursor Monks to keep intruders away from sanctified areas. They are positioned in front of an area and will activate a defense mechanism when approached by intruders. These defense mechanisms employed include electricity, floor spikes, and wall spears. They are mostly concentrated within the Monk Temple, though there is one guarding a warp gate in the Great Volcano.
Sentries eyes are large, floating eyes with a blue aura around them. They have a faint crown around their eyes with faint blue crystal-shaped designs on them.