Servo rust

Servo rust is a disease from the Robots in Disguise portion of the Aligned continuity family.

Servo rust is an aliment that is, it would appear, quite persistent, pernicious, and all but impossible to eliminate once you have it. It may be more of a lingering annoyance than an actual mortal threat.

Fiction

2015 Robots in Disguise cartoon

Upon learning of the return of the long-thought-dead Starscream, Optimus Prime grumbled that the Seeker was "harder to eliminate than servo rust". Mini-Con Madness