The Prototype Gogg was an experimental machine developed by the Zimmad company to fulfill the Principality of Zeon army's requirements for an amphibious mobile suit. Its development was conducted on a space colony, and it was tested after being transported to Earth. It was the first mobile suit of the Principality of Zeon to have built-in mega-particle weaponry, but since the diffusion of the guns was more serious than expected, the plan was to equip it with torpedo pods on its arms as optional equipment. However, tests on Earth showed that the arms would have resistance problems when navigating underwater for long periods of time and over long distances, so the mass-produced model adopted a structure in which both arms could be extended and retracted. As a result, the torpedo pods were scrapped, and the mass-produced models adopted a method of mounting the torpedoes in the abdomen. The manipulators on both arms are shaped like claws, but at this stage they are not iron nails, and have many joints.