This is amazing! The coin appears to be jumping around on the ice--all by itself! What's going on? Why does it move this way? Lisa Winter of IFL Science explains:
When the half dollar is pushed into the block, the warmth of the metal sublimates the dry ice and causes a change in pressure. As the gas pushes past the coin, the pressure causes that shriek. After some time, the coin forms a larger hole in the dry ice, producing larger air currents that push the coin around, causing it to vibrate and appear to be shivering.
-via Rocket News 24