How to get one..
Okay to get an animated comment box you use do what you do to get an image comment box. Go on edit profile, and paste the direct link of the animated image in 'text input/ textarea background image' and then you have an animated background image. Here are some you can use...
Music
http://i18.photobucket.com/albums/b124/dumbasablond22/animated/music.gif
Donald duck
http://i826.photobucket.com/albums/zz187/kkelseyllindsay/animated/lisalindsay63gif.gif
Flower tree
http://i942.photobucket.com/albums/ad269/NewBeginnings2/Animated%20Scenery/1099525-bigthumbnail-450x253.gif
Stars
http://i793.photobucket.com/albums/yy220/terresajames99/animated%20backgrounds/colorful-stars-glittering-animated.gif
Swirls
http://i123.photobucket.com/albums/o285/jane_doe_102/BACKGROUNDS-ANIMATED/fractal4.gif