Transformers: The Return Of Optimus Prime (1987)

When Scientists discover Sun Spores, an alien plague that instills a hatred so overwhelming that anyone infected won't stop until everything in their path is destroyed. Soon, the scientists decide that it's time to rid the Earth of the Transformers and plan to use Optimus Prime's lifeless body to lure every Transformer to their lab and infect them with the Sun Spores. When the Sun Spores outbreak rages out of control, the universe's only hope is to revive Optimus Prime. But even if Optimus recovers, he and his Autobots will need to rely on Galvatron and the remnants of his Decepticons to help reclaim the Autobot Matrix of Leadership from an infected Rodimus Prime and use it to unleash a new Golden Age of Cybertron.

Unfortunately the movie Transformers: The Return Of Optimus Prime is not yet available on HBO Max.