Holographic Cube

The Holographic Cube is an object that appears in the Sonic Underground television series. It is a cube used for communication purposes.

Description
Holographic Cubes are white cubes that can fit into the palm of one's hands. When used with a certain device, the can project holograms and pre-recorded sounds in order to send messages to others.

History
Bartleby received a Holographic Cube which contained an invitation to a demonstration of a De-Roboticizer. Sleet also got his hands on one, and presented it to Robotnik, who instructed for him and Dingo to go and investigate.