Eww, its all squishy!

The video shows a mixture of cornstarch and water (sometimes referred to as Oobleck) placed on top of a sub-woofer. This cornstarch mix is a Non-Newtonian fluid and more precisely a Dilatant material. In short, the application of force, in this case the vibrations from the sub-woofer, cause the material to thicken. Science is fun! Woo!