Tornedron

Tornitron was the succesor to Unicron, created by Unicron's creator Primacron. Unlike Unicron, Tornitron was an energy-based lifeform, controlled by Primacron's remote control. It consumed other energies, leaving stars dead and planets inert; its final purpose was to leave the entire universe a blank slate for Primacron to do with as he pleased.

Unfortunately for Primacron, while Tornitron succeeded in draining most of the universe's energy, it also became just as rebellious as his predecessor. Only Grimlock defeated it before the creature could consume its creator; he threw it into reverse, returning all the energy it stole to its original locations and dispersing the entity.