Rust rash

Under certain malign conditions, Transformers may develop a rust rash.

Fiction

Marvel Comics continuity

Straxus once had a rust-spot rash. In error-filled form, the information made its way to Scrounge who reported to the other Autobots that Straxus was dying. The Smelting Pool!

The Technobot Lightspeed is allergic to most fuels commonly consumed by his kind. This means he must always take a special lead sulfide additive when refueling. If he doesn't, his engine will experience severe knocking, a rust rash among the consequences. Lightspeed's Universe bio

Dreamwave Armada comic

Leader-1 felt that Megatron treated him like a rust rash. Galvatron's More Than Meets The Eye profile