Watchdrones are mechanoids found in Metroid Prime 2: Echoes. They were built by the Luminoth in order to prevent the Ing from accessing key areas. They do not have any offensive capabilities, but are indestructible and will position themselves so as to block narrow passages. However, they will move when exposed to light. Samus encounters two Watchdrones in Dark Torvus Bog blocking the path to a Sky Temple Key. They are situated directly below Light Beacons that Samus may activate in order to make them move.
- "Watchdrones were built by the Luminoth to guard key areas and hinder Ing armies. Most of these units have betrayed their masters, and now serve the Ing. Watchdrones are indestructible and reluctant to move, but can be forced into quitting their posts by exposing them to bright, pure light. Once the light fades, the mechanoid will return to its original resting site." — Logbook "Watchdrone" (Metroid Prime 2: Echoes)