Enforcers are large four-legged machines designed by Tachyon allegedly for the lombaxes, but in reality to wipe them out. Modified from the original purely robotic design seen in blueprints, their skull-like heads were replaced with a liquid compartment so they could be operated by drophyds and serve as heavy infantry in the Imperial Army. The two rapid fire turrets attached to the sides of the Enforcer were there primary method of attack.
Stationary variants of the Enforcer are present at the outer section of Zordoom Prison, they remain surrounded by a green energy shield and only go into combat mode if the searchlights within their sector are breached, those versions are known as the Drophyd Enforcer Turrets.
Pre-Ratchet & Clank
The blueprints of this machine Tachyon supplied the lombaxes were similar to the Imperial Army's model, albeit the early prototype lacked a dome for a drophyd to pilot, rather it contained a skull like head instead, suggesting this Enforcer was a robot rather than a mech. This early Enforcer model was originally designed by Tachyon with the aid of Lombax technology, under the request of Azimuth to build weapons in order to protect the Polaris Galaxy. Tachyon; however, had no intention of aiding the Lombaxes, rather he planned to render them extinct for what they did to the Cragmites. When Tachyon was able to obtain the raritanium needed to buy the drophyds' loyalty, he modified all existing models of the Enforcer by removing the skull-like head and replacing it with a dome for drophyds to operate from.
Behind the scenes
Although the Enforcers were not meant to be fought on planet Kerwan, one was briefly encountered after a warp pad, and then hopped away leaving Ratchet to fight the drophyd troopers on the balcony. However, if a Groovitron was deployed before the Enforcer hopped away, it would remain there and continue to attack Ratchet like normal, although it could not be damaged by means of weapons or devices.
Another Enforcer that was seen on Kerwan could actually be killed; this Enforcer was seen hopping from building to building as Ratchet took a warp pad to the sky bridge, before firing several shots and leaping away. However, if one was to deploy a Groovitron before jumping onto the warp pad, the Enforcer would leap right into it, causing it to stop and begin dancing mid-jump and fall to its death. However, when it falls it doesn't explodes like usual.
A purely robotic Enforcer appeared battling Ratchet on Kerwan in the opening and ending cutscenes of PlayStation Move Heroes. He was defeated when Ratchet damaged his knee: disabling his internal retro-formation modulator.