Patrol Robot

"Forever patrolling the halls of the monastery; one sound and you'll have some high-speed visitors pummeling your chest!" A Patrol Robot is an enemy found in Rise of the Triad.

Strategy
The Patrol Robot moves along a set path, keeping watch over an area. If you fire a weapon, or get too close, it will stop in its tracks and shoot powerful exploding discs. Once you leave, it resumes its patrol.

Like bosses, it's immune to bullet weapons. There will usually be a rocket launcher or two nearby, but since they don't follow you, you could just slip past them and save the ammo. Most rocket launchers can take them out in a single shot; the Drunk Missile is probably the worst to use, because it takes several rockets and most of them will likely miss. Also, you don't need to lead your shots with rocket launchers, since they stand still once you shoot at them.