This is a video demonstration of Kinetic Sand, a sand play toy made from 98% sand, and 2% Polydimethyl siloxane, a "silicon-based organic polymer...particularly known for its unusual rheological (or flow) properties." It makes the sand act...weird. Also, at $45 for 5kg (~11 pounds) of Kinetic Sand, it sounds like either polydimethyl siloxane is really, really expensive, or somebody's price gouging. Just saying, I'll sell you a bag of cat litter mixed with paint thinner for $10. It might not act the same, but neither will your kids after they eat a handful.
C OINTINEU FOR HTE VIDEO (I'm typing with my elbows).
Thanks to Roland, who may or may not be a headless Thompson gunner. In my mind he is though.