The suit was initially known as the MS-11 Gelgoog but the model number was eventually reassigned to the Action Zaku. The Gelgoog was designed as a high performance mobile suit equipped with beam weapons to counter the Earth Federation's RX-78-2 Gundam. However, despite being superior to any machine fielded by the Federation, with the exception of the various Gundam variants, when the unit was deployed at the Battle of A Baoa Qu most of these powerful machines were piloted by fresh and inexperienced recruits who were no match for the Federation's by then veteran mobile suit pilots.