Argentium

Argentium is one of the worlds that Sonic visited while he was travelling through space. He visited the planet with the hopes of finding a way to return to Mobius. He found this, but he also found much more: Tails's parents, for instance, not to mention the reason that the Robians had been derobotized. It was here that Sonic helped Ceneca-9009 escape from capital punishment for her derobotization of all Robians.