The Last Weekend (2012)

Episode Overview

Megatron unleashes a dangerous plague known as Cosmic Rust upon his Decepticon allies. In a bid to find a remedy, he captures Perceptor, who ultimately discovers that element X can reverse the effects. The Decepticons are healed, but they turn on Perceptor, using him to infect the Autobots with the very same Cosmic Rust. Meanwhile, the supply of element X dwindles, putting everyone at risk.