What is the only toy that can act as a sponge, water balloon, baseball, and marble? Slippery Spheres Fun Science Mini Set by DuneCraft! This fun science kit allows kids to easily grow their own cool slippery spheres. These amusing things can be thrown, bounced, slipped, slid, and exploded! This enjoyable plaything from Educational Toys Planet starts out the size of small seeds. After less than a day of being in water, the spheres will grow to more than 200 times their size to a size of a marble! This fun experimental kit from Educational Toys Planet is also perfect as party favors or small gifts. Slippery Spheres Fun Science Mini Set by DuneCraft are also completely eco-friendly, with no toxic materials used in their creation.