It is a blimp that flies in a circle around your avatar's head. The scrolling marquee displays the message "NO ASL! CHECK MY HOMEPAGE".

The animation is actually much slower. Very smooth movement and seamless loop.
The marquee has an opacity map for more flexibility.

The textures are as follows:
(Links are direct to image)
Texture 0: Marquee and Marquee Opacity
Texture 1: Body
Texture 2: Bow and Fins
Texture 3: Cabin