Cybertonium

Cybertonium is a green, crystalline element found only on Cybertron and is used in construction of Transformer bodies on that planet. Such Transformers bodies use Cybertonium in a manner which depletes it over time, requiring it to be replaced. As the element dwindles within a Transformer's system, its deficiency causes minor malfunctions, such as an inability to fully transform or control one's actions, but if the depletion proceeds past a critical level, it can lead to death. Cybertonium is mined from a pit deep in the planet.

While seemingly vital to most Transformers, those with bodies created on other worlds do not require the element.

Generation 1 cartoon
After fleeing from a battle with the Dinobots, the Decepticons began to suffer minor malfunctions which they attributed to bad Energon. Attacking a power station to refuel, the Decepticons were confronted by the Autobots, but the battle devolved into a stalemate as both sides began to suffer from increasing malfunctions.

As their conditions worsened, Perceptor concluded that both sides were being affected by Cybertonium depletion. Having also learned the real problem, Megatron contacted Shockwave and had him prepare a shipment to be sent over the space bridge. Both factions sent groups of Transformers created on Earth and thus fully functional, the Dinobots and the Constructicons, to retrieve the shipment. Both groups fought and ended up destroying the Cybertonium, with the Dinobots ending up on Cybertron and refusing to assist those on Earth. With the Autobots fading fast, Spike and Carly, over the objections of Optimus Prime, traveled across the space bridge to get some more Cybertonium.

Arriving on the homeworld of the Transformers, the human pair avoided Shockwave but damaged the computer controlling the space bridge and prevented even the Decepticons receiving more of the vital element. Searching Wheeljack's lab, Spike and Carly ran into Swoop, who explained that the Dinobots had been captured and reprogrammed to work in the Cybertonium Pit. When the humans and Swoop attempted to rescue their friends, they were captured in turn and forced to work in pit as well. After Carly re-reprogrammed the other Dinobots, the group was able to escape back across the now-repaired space bridge with enough Cybertonium to save their fellow Autobots.

Headmasters animated series
During the Headmasters conflict, Vector Sigma developed an alloy called Cybertonuron that was many times stronger than Cybertonium.

Items of Note

 * The introduction of Cybertonium throws a spanner in the works for determining the origins of the newer second-season characters such as Perceptor, Blaster, Blitzwing, etc. Previously, it could be assumed they had simply arrived from Cybertron or some other planet, but the fact that their Cybertonium deteriorates in exact sync with the earlier characters suggests that they were also aboard the Ark and went through the same four-million-year slumber as the 1984 characters. Why we didn't see any of them for the first year is therefore a bit of a mystery within the context of the stories.


 * Likewise, it adds to the controversy surrounding the origin of the Constructicons. The fact the group can function and even form Devastator would seem to imply they were created on Earth, as seen in "Heavy Metal War", yet later in season two, "The Secret of Omega Supreme" states they were originally from Cybertron. If the Constructicons were merely rebuilt on Earth, why can't other Transformers be rebuilt in similar fashion so as not to require Cybertonium?


 * While Cybertonuron is noted in Headmasters as being many times stronger than Cybertonium, stated with the implication that Cybertonium is unusually strong itself, there is nothing indicated in either "Desertion of the Dinobots" episodes that it's metallic or used in an alloy.