Geosensus is highly specialized for his function as a fuel deposit scout. His job is all he cares about and he has extensively adapted and reconfigured himself for its sake, in the process sacrificing features both physical and emotional that most Transformers take for granted. A pacifist, he long ago decided never to be outfitted with weapons, instead covering his body with sensory technology. As energon grew scarcer throughout the millennia, he configured himself with scanning and sampling devices requiring such precise calibration and delicate treatment that they had to be permanently fixed into position: thus he could no longer transform and would always be in his alternate mode, a mobile all-terrain scanning and mining array.
These sacrifices allowed him to help his teammates, but also alienated him from both major Transformer factions. That alienation would cost Geosensus everything.
—No lesson to learn. No reason to tell.
Transformers Legends anthology
While searching for energon deposits, Geosensus discovered Megatron's underground death matches. He watched the grisly battle between Grabber and Sting, and was confronted by Megatron himself. Megatron presumed Geosensus to be a volunteer for the death matches and thus a potential Decepticon recruit, and so he immediately "adopted" Geosensus, speaking to him in a manner both brutal, commanding, and strangely personable. When Geosensus revealed his pacifist nature and asked "Why would a Cybertronian need weapons on Cybertron? We have no enemies here...", Megatron grew enraged and tried to kill him. Interrupted by the arrival of police units, he settles for brutally mangling Geosensus before making his escape.
Before going off-line, Geosensus had managed to send an emergency beacon to Autobot commanders. The Decepticons promptly attacked and devastated Kaon. While Geosensus' warning couldn't help the Autobots repel that attack (Optimus Prime would later sadly assert that nothing could have), it did give them time to evacuate many civilians to safety, and so Prime would always look favorably upon Geosensus after that.
Millions of years later, the Great War in full sway, Geosensus would join the Autobot crew aboard the Ark. En route to Earth, Prowl objected to Geosensus' presence among the crew, because he not only wouldn't fight but also wouldn't transform into robot mode and thus couldn't socialize and bond with teammates. Optimus countered that Geosensus had made that choice millennia ago and in the meantime was fulfilling a valuable function.
When the Ark crashed on Earth, Geosensus was the first Autobot to be awakened by Teletraan I, and promptly set about exploring the planet for energy. He marveled at the extreme abundance of carbon-based fuel sources, and in general enjoyed himself greatly as he took core samples and electromagnetic readings. His enjoyment was interrupted when he was attacked by newly-awakened Decepticons. Out of sheer desperate self-preservation he transformed into robot mode for the first time in millions of years and killed one of the Decepticons with frenzied flailing punches. Geosensus was horrified at having destroyed his fragile sensory equipment and fighting a member of his own species. He had little time to reflect on this, as the surviving Decepticon continued strafing him from the air.
Hoping to find reinforcements, Geosensus ran back towards the Ark, where by that time Optimus Prime and Prowl had been awakened. When they saw a Decepticon and an unknown robot approaching their base, the two Autobots assumed they were under attack. Prowl killed the Decepticon, and Optimus Prime killed Geosensus.
On examining the wreckage they learned the truth, and Prime was shocked and despondent. He tried to think of how to explain this to the other Autobots, but Prowl insisted he should do no such thing. Prowl reasoned that with the Autobots already on the defensive and now stranded on an unknown world, they could not risk losing morale as well. His argument was that just as Geosensus had chosen to give up so much in order to specialize as a fuel scout, the lowly archivist Optronix had chosen to give up being a normal flawed Transformer when he accepted the Matrix of Leadership and became Optimus Prime. The Autobots needed an icon of heroic and infallible leadership more than they needed a fuel scout. Besides, it was unlikely any of them had even noticed Geosensus, a loner who was always in his altmode and often underground. Optimus Prime, humbled, eventually agreed.
Prowl recycled some of Geosensus' body parts and covered up all evidence of the killing, and swore that if it ever came to light he himself would take the blame for it.
- The descriptions of the flying Decepticons on Earth are confusing. They are alternately described as "probes" and "aerial units" with varying color schemes, yet Geosensus is still devastated by having killed one. Perhaps the author was thinking of the Diagnostic Drones that also appeared in War Within, or the reanimated Seekers who would come to assist Megatron in other Dreamwave fiction.
- Geosensus himself is described as being huge: in vehicle mode he can barely fit through a door large enough for Optimus Prime, and in robot mode he crushes the attacking Decepticon with a "massive" arm. His scanning-mining-array-thingie mode can move its equipment to allow him to express himself with emotive body language.
- Speaking of vehicles expressing themselves, Megatron's tank mode is said to have a giant mouth that drools and spits as he speaks.
- Now that you know the truth, Prowl has to kill you too.