I'm totally jacking that gif for me avatar.
Edit: Booooo it's too large...how does one go about resizing a gif without breaking it?
You need a program for GIFs.
But if you want a GIF as your avi, you might wanna talk to one of the MODS first and they will tell you what size the gif can have. Also, they have to work some of their magic to make your Avatar work...
Just contact one of the Mods and tell ask them about it.
EDIT: I modified it for you, on a site:
Still, talk to a mod about puting it in your avi.
Or try doing it yourself, but i don't know if it's gonna work