thanks , tis appreciated.I used Flash Professional, animated my original 'tar, exported as png sequence and used a free app called GIFfun* to make the images into an animation.
*I used GIFfun because Flash has terrible gif export.
If you don't have Flash you could make several copies of your 'tar and gradually darken each frame in Mac OS X Preview, then drag the folder of images into GIFfun.