From Sonic Retro

While exploring the Voxai Colony Beta in Sonic Chronicles: The Dark Brotherhood, Sonic and friends happen across Croesus, a Voxai citizen who finds his connection to the Overmind severed entirely - a state of affairs which, while it saves him from the psychic domination afflicting other Voxai, is nonetheless slowly driving him and his family insane from deprivation.

Further searching of the Colony reveals the source of the problem: what looks very much like a Nocturnus Clan Black Ops team is operating in the north. Tails discovers that the echidnas have deployed some sort of experimental signal-blocking technology to interfere with the Overmind's psychic connections. On defeating the Nocturnus and shutting down the device, Croesus reverts to normal.

The mission, however, can serve up tension between Sonic and Tails. While examining the device, the little fox's enthusiasm to discuss its technology with Eggman can draw Sonic's anger - Tails having apparently having forgotten that the Doctor encases cute forest animals in walking coffins and nukes heavily-populated cities as a matter of course, and so it's not necessarily a good plan to give him ideas.