Crowd pummeler

Crowd pummelers are cheap and easy-to-maintain devices made for sentry duty. These constructs are made of red pipes and pistons, and have one green robotic eye that they use to watch the area around them.

The gnomes of Gnomeregan used these robots to patrol their streets and bash anything they notice that violates the laws programmed into them. Since Gnomeregan's fall, most are programmed to attack anything that is not a leper gnome.

Crowd pummelers recognize Common, but only an experienced tinker, using the correct technological codes, may command them. In the past, a pummeler warned nearby violators aloud, giving them a short time to halt their offenses, but now all they say is "Intruder!" before charging.

Crowd pummelers lack finesse, simply charging into combat and smashing any enemy in sight. If multiple crowd pummelers are commanded to capture a target, one bashes and others deal nonlethal damage.

In World of Warcraft
Since then many different models of these have been produced by gnomes or other capable engineers and appear in more areas than just Gnomeregan.