Organic Core

The organic core was a greenish, amorphous substance at the center of Cybertron, apparently the concentrated essence of the planet's long-dead organic life. Substance from the organic core was essential in Optimus Primal's original mad plans to purge Cybertron of machines, and later turned out to be a means of restoring control of Transformers' bodies to their true spark.

Megatron targeted the organic core in his plans, rightly seeing it as the one thing needed to make Cybertron a "perfect technosphere." When Megatron and Primal fell into the organic core in the final battle, its energies were released to make Cybertron a technorganic world.