Hate Plague

The Hate Plague was one of the few maladies capable of affecting Transformers. Any organism, when infected, turns bright red and displays incredibly high levels of agression toward everything and everyone.

It was first discovered in the 2-Part episode The Return of Optimus Prime in the third season of the G1 Cartoon, aboard the same starship that was carrying Optimus Primes body.

Though never elaborated upon exactly, the Plague was eliminated by Optimus unleashing the Power of the Matrix.

In Beast Machines, Megatron uses a new variety of virus based on the Hate Plague in an attempt to destroy the Maximals.