From Copernicus (because I can't really paraphrase this!):
Our Department of Planetoid shrinking used the patented Nano-o-Tron on a neighboring planet to create this wonderful rheoscopic toy. Rheoscopic, what? Rheoscopic fluid is a special material that shows currents. Within this planet's shell you will see fluid dynamics visualized in spectacular ways.
This SWOLRD's shell is strong and resilient like you! You can bounce it. Give it a twirl and watch a bazillion microscopic shimmering particles flow. After the turbulence, the SWORLD will calm and the particles will settle.
Note: Please keep out of direct sun and away from heat.