The original robo-scorpion was created before the Great War by Dr. Mobius and his team in the X-42 robo-warfare facility in Big MT, based on scorpions and powered by a fission battery. They were created for security at the Big Mountain Research and Development Center as robotic guardians with a tail-mounted energy bolt blaster, optical systems allowing anyone in the X-42 robo-warfare facility to see through them with monitors, and a self-destruct sequence which, after their death, causes electrical explosion damage to anyone around. Additionally, their public address systems allow anyone in the X-42 robo-warfare facility to speak through them. According to Mobius, they can form themselves from floor panels along with any other random parts lying around. X-42 giant robo-scorpions, unlike the others, were a project for the US military. Despite 18 prototypes being requested, certain kinks in design and programming prevented them from reaching battlefield deployment and only one functional prototype was completely finished, remaining idle in the X-42 robo-warfare facility.
Sometime after the Great War, Mobius hacked his colleagues and altered their personalities, chronometers, geometers and more. Disgusted by his own actions against his friends, Mobius erased some parts of his memory to ease his conscience, including the knowledge of his creations. Later, Mobius relocated to the X-42 robo-warfare facility which he renamed the "Forbidden Zone." There he began to "re-create" the robo-scorpion, now based on the radscorpions which occasionally wandered into the Big MT. He added the suffix "b" onto his new creations and retained all features of the pre-War model. He also took control of the previous models of robo-scorpions making them his personal army. Mobius now uses the robo-scorpions to constantly distract the Think Tank.
Robo-scorpions are very fast and extremely resistant to most damage. Pulse weapons are less effective against them compared to other robots. The X-42 giant robo-scorpion is a special model adorned with Saturnite armor plating, making it virtually impervious to small arms fire, but is vulnerable against pulse weapons . Its tail is equipped with a powerful atomic laser that draws its energy from an internal generator. The laser is capable of causing severe damage and leaving residual radiation of about 30 rads per second for one second, as well as having a blast radius of about 3 meters. It is also equipped with a self-destruct system like other robo-scorpions, but detonates a small nuclear device instead of an electrical explosion. The X-42 giant robo-scorpion's self-destruct explosion leaves radiation of about 15 rads for the first second which decreases every subsequent second, stopping after five seconds.
Robo-scorpions appear in Mk. 1-5 and Mk.1b-5b (Data for Mk. 2 and Mk. 2b exist, but both are unused), and come in pincer, blaster, and bomber variants, as well as different sizes relative to their Mark. Their appearance in the game depends on the player level and importance of the location in which they appear.
Encountered in the Forbidden Zone dome during the Old World Blues quest, the X-42 giant robo-scorpion is a unique robo-scorpion and Doctor Mobius' ultimate guardian. It is armed with a powerful atomic laser capable of causing severe damage and radiation damage of about 30 rads per second for one second as well as having a blast radius of about that of a pulse grenade.
It sometimes fires at you while you are behind cover, and you will still absorb the reduced amount of radiation, about 2-15 rads per second.