The Magic of Sulfur Hexafluoride

For those of you who haven't seen it (pun intended), Sulfur Hexafluoride is a colorless, odorless gas.  It's also much more dense than air, which means you can do some cool stuff with it.

Observe the video.

https://www.youtube.com/watch?feature=player_embedded&v=u19QfJWI1oQ