Geigerrock Gevlar works for the Gandora as a member of the evil Rock People. He often operates with fellow evil Rock People Devilrock and Doublerock. He can summon images of himself to confuse enemies with his Dark Illusion Fist. He can turn into a large radioactive space crystal rock and if shattered he can reform. He can pass though solid rock with ease. He is immune to acid. Because of his mechanoid nature, Geigerrock does not need to breath oxygen. He stands 6 feet 7 inches tall and weighs 1.15 tons. His weapon of choice is his Atomic Death Fork which can fire his Alpha Beam, but he also carries an automatic rifle into combat. He occasionally pilots a Rock Commander craft.
Geigerrock Gevlar first appeared in Machine Robo: Revenge of Cronos episode 20, "The Man From Gandora". He and his partner Devilrock Clay were sent by Gades to destroy the Rock People ruins near Korora so they could uncover an energy source. The local Rock People fought back by attacking them with bombs. The bombs forced Devilrock to seek shelter in a cave where he was attacked by Iron Eater plants. Devilrock briefly rejoined his partner Geigerrock on their mission, killing a Mecharock and Gutsrock, but when Reina Stol rushed onto the battlefield Devilrock sacrificed himself to save Reina from Gevlar's Alpha Beam. Geigerrock was defeated by Viking-Fu and was thrown into a field of Iron Eater plants.
Devilrock, Doublerock and Geigerrock returned in episode 21, "Angel of the Mind, Vikung-Fu - Protect". Members of the Gandora forces took control of the population of Cleo City. The Evil Rock People were attacked by Rom Stol, but he was quickly overpowered with Wiseman's control powers. Although Rom and his companions were temporarily subdued by Wiseman. Blue Jet slashed the three evil Rock People with his sword. Once the three realized the people of the city were free and fighting back, they retreated.
Geigerrock returned in one piece in episode 24, "Gather All Machine Robo". Devilrock and Geigerrock ambushed Rom just before he made it to Yamalin City, but he fought them off. Later, Devilrock, Doublerock and Geigerrock followed Kendo Robo into the desert in his quest to recover ammunition for his city. When Kendo Robo was attacked by Geigerrock, Triple Jim defended him.
In episode 28, "Tough Trailer - 10 Seconds to Detonation", Devilrock and Geigerrock were part of a Garudi lead Gandora force who attacked the Yamalin City computer center by sneaking inside the city in Tough Trailer's trailer.
Devilrock, Doublerock and Geigerrock appeared in episode 30 "Spew Fire, Big Blaze Cannon". The three evil Rock People fought Tough Trailer and Reina Stol, but Devilrock ordered his people to retreat when Pro Truck Racer arrived to help his brother and shot one of the heads off Doublerock. When Rom Stol arrived he cut one of the arms of Geigerrock with his Wolf Sword.
Devilrock and Geigerrock appeared in episode 37, "Critical Moment - Land Commander 5", attacking Yamalin City. Note: Devilrock and Geigerrock's appearance in this episode is stock footage from episode 28.
In episode 38, "Raise Your Gun Helitranser", Amazonrock, Bloodyrock, Devilrock, Doublerock and Geigerrock were part of a large Gandora team lead by Ashura that ambushed Rom Stol and his allies. Note: Geigerrock's appearance in this episode is stock footage from episode 28.
- Bandai Machine Robo: Revenge of Cronos MRGR-2 Geigerrock (1986)
- A new mold by Bandai. Turns from robot to rock. Comes with his Atomic Death Fork.
- Shares a mold with Rock Lords Tombstone.