Rarified Energon

Whereas normal Energon provides the fuel that keeps Transformers living, Rarified Energon is something more. It is the base material of all Transformer life; the Transformers' physical forms and the stuff of which sparks are made is Rarified Energon. Rarified Energon is also apparently of limited supply throughout the multiverse. So, if it all were to be used up, Transformer life could no longer come into being, rendering the species extinct or doomed to be so. Given this, its protection is extremely important to Primus, and he has tasked Nexus Prime of the original Thirteen Transformers with its protection. Crossing Over: Part 6

The Autobots would later move this resource frequently to keep it out of the hands of the Decepticons. However, Gigatron would manage to track its location to Ironworks. Invasion Prologue