Sphero WaterBall Housing Accessory - #Make5000

This Sphero WaterBall Housing Accessory is my submission to the Sphero #Make5000 competition.
It allows the Sphero to move through the water more quickly and easily.
It should be sold with the Sphero Nubby. The Sphero would go inside the Nubby, which would then be placed inside the WaterBall Housing. The Nubby would create friction so that the Sphero wouldn't spin freely inside the housing.
Or, the design could be downsized and made of a rubber-like material so that the Sphero could be pl