(And don't say Jerjerrod isn't in ESB. He has been since the whole "Alert my Star Destroyer to prepare for my arrival" was dropped in.)
I've tried to find a picture, and can't find one. (Plenty of shots of Jerjerrod in ESB, but always a frame too early or too late to show this thing.)
It's some sort of droid, and looks like it's about a foot and a half tall. Glossy black, and shaped almost like the EU Cloud Car toy from a few years back, only with less detailing. It's visible behind Jerjerrod for a split second, gliding in the direction of Vader's shuttle. Definitely not a mouse droid (as we see a clear shot of a mouse droid a bit earlier, and it's much smaller and blocky).
Anyone have anything?