|This object exists primarily or exclusively within the Sonic Underground continuity.|
Information in this article may not be canonical to the storyline of the games or any other Sonic continuity.
The canister is yellow with six green ridges around it to hold the lid. It is decorated with swirl like patterns with red circles. Its shape is similar to that of a bottle with "fins" for stability. The very top of the lid has a glowing green gem. Inside the canister is a larger green glowing gem.
Seeking a way to contain the destructive power of a broken Chaos Emerald, Knuckles the Echidna sought his great-grandfather Athair for guidance. Athair gave Knuckles the canister and advice him to form an allegiance with Dr. Robotnik for it to work. Getting Robotnik to collaborate, Knuckles caught the Emerald fragments in the canister after they made an out-of-control Dingo relinquish them, stopping the chaos from doing further harm to Mobius.