is a port of an old prank/joke control panel for System 7 called Earthquake. When installed, your Mac will experience random earthquakes. This version is a bit different from the old one, but the principal is still the same. Ideally, you should install this on the computer of someone who is smaller and weaker than you.
If you wish to quit EarthquakeX, simply open up a Terminal window and type:
killall QUIT "Earthquake"