The Chaos Energy Cannon is large orbital energy laser weapon that appeared in the beginning of the Unleashed Saga. This device was created by Dr. Eggman with the of purpose awakening Dark Gaia form the planet's core.
At some point prior to Unleashed Saga, Dr. Eggman learned of the existence of an ancient hyper-energy organism of limitless power called Dark Gaia. Seeing that this creature could provide him with the energy needed to finally create Eggmanland and take over the world, Dr. Eggman sought out to harnessing this creature's power. With the information provided by the Gaia Manuscripts, which the doctor had stolen from Professor Pickle, Eggman figured out a way to awaken Dark Gaia from its slumber within the planet's core. To this end, Dr. Eggman constructed the Chaos Energy Cannon. Its function was to take the seven Chaos Emeralds and reverse their polarity, thereby creating a negative Chaos Energy blast that would force Dark Gaia to awaken from its slumber, before it was meant to awaken. For the Chaos Energy Cannon to work however, Dr. Eggman needed the seven Chaos Emeralds, which presumably was in the possession of Sonic the Hedgehog. The doctor then orchestrated a plot where he would launch a space armada of his Eggman Fleet and threaten to take over the world, with the purpose of luring Sonic and the Chaos Emeralds, which the doctor anticipated Sonic would use against him, into his Chaos Energy Cannon.
Dr. Eggman's plan eventually proved to success, as Sonic arrived at his fleet and turned into Super Sonic. Having disguised his Chaos Energy Cannon as a harmless looking space station, Dr. Eggman tricked Super Sonic into chasing him into the center of the cannon, where he managed to trap him in an energy shield, and robbed him of the Chaos Emeralds, thus completing his Chaos Energy Cannon and allowing him to awaken Dark Gaia.
In the end, the Chaos Energy Cannon was a one-sided success as it managed to carry out its function of awakening Dark Gaia, but it would also wield some additional undesired results as well; even though the Chaos Energy Cannon managed to awaken Dark Gaia, the beast had not yet matured enough to awaken properly and as such broke apart and scattered across the world, which left Dr. Eggman with task of reconstructing it. Additionally, the feedback created from the Chaos Energy Cannon caused some of Gaian energy to infect Sonic, thus giving him the ability to transform into Nightmere Sonic the Werehog. The process also left the Chaos Emeralds drained of all their power, which let to the doctor discarding them with Sonic. This however proved to be his own undoing as Sonic later used them to undo the Chaos Energy Cannon's work.
- The Chaos Energy Cannon's name was revealed by Professor Pickle.