Second Curtain Flash Fun

I was playing with a flash setting on my 580ex called second curtain synchronization.  What it does is cause the flash to fire just before the shutter closes. Normally the flash fires immediately when the shutter opens.  So when you set the exposure for like 1/4 of a second, it will fire at the end of the 1/4 exposure.  Now if you move the camera as the shutter is open, you get this nice artistic motion effect.  It gives Happy a ghost like effect.