- Cosmic Rust is a disease in the Generation One continuity family.
Cosmic Rust is a microorganism that devours Cybertronian metals. An infected Transformer starts growing a rust-like substance all over their body. Eventually, the corrosion causes the Transformer to waste away to nothing. Perceptor describes it as the Cybertronian equivalent of the Bubonic plague, the "Black Death".
Fiction
The Transformers cartoon
Cosmic Rust was first discovered in the ruins of an ancient Autobot colony in deep space, on the planet Antilla. The Decepticons who visited the planet were accidentally infected by the rust courtesy of a stray meteor. The radiation provided from a weapon found on the planet (known as The Lightning Bug) caused the virus to accelerate substantially.
The only cure for Cosmic Rust was a substance called corrostop, invented by Perceptor to remove corrosion of any form and protect substances from future corrosion. Cosmic Rust
Binaltech
A new and improved 'Cosmic Rust' disease once again surfaced in the year 2003, thanks to Swindle's tampering. Here, the Decepticons flood the Earth with it, destroying the original bodies of most of the Autobot garrison stationed there - before apparently backfiring on the Decepticons once again. The bulk of both forces however was unaffected as the bulk of the war's fighting has shifted to the Cybertronian-Theater. The Rust itself is never cured, but thanks to a fusion of Cybertronian technology and human car manufacturers, new temporary-bodies were built for the damaged Autobots. While the Decepticons had to resort to Mind Control in order to trick the human engineers into building them bodies of their own. Binaltech
Shattered Glass
Nightbeat, head of the Autobot Secret Police, suffers from a chronic case of Cosmic Rust due to a failed assassination attempt. Though usually kept in check by an unspecified treatment, it can flare up and cause him to malfunction and become contagious if not monitored continually. Shattered Glass
Transformers Animated
Oil Slick often made use of cosmic rust against Autobots. After attacking an Autobot base that held a Space bridge, only Rodimus Prime stood in their path; Oil Slick dispatched him by throwing a vial of cosmic rust on him. TransWarped
Dark of the Moon film
Sentinel Prime uses cosmic rust shot from a blaster to murder Ironhide. It is a powerful weapon and doesn't just infect him with cosmic rust, but causes horrific exterior damage to Ironhide.
As for the weapon in general, not many Autobots like it, as they thought it was something the Decepticons would likely use, and wasn’t up to their honourable standards.[citation needed]