[ques] how did they create this effect??? - MTV2 "double dutch"

http://www.stashmedia.tv/video/stash07_trailer.htm

toward the end of this trailer is a brief MTV2 clip
where a silhouette of a two headed dog emerges on the
screen with lots of scribbly lines "coloring-in" the
image.

does any know how this effect was done?
or a way to get it done using AE?

in case you want to view the whole MTV2 spot, you can
watch it here: http://www.pureny.com/
the clip is called "double-dutch"

thanks,
steve