This is Hela's Glider Mouse that looks odd as hell, but supposedly works pretty well. Rather than being to the side of the keyboard, like traditional mice, the Glider Mouse sits between you and the keyboard. The little knob simply glides around the trackpad. Supposedly the mouse is more ergonomic by preventing the need to stretch out for that mouse.
The glider mouse retails for $285 dollars, which is way too much. I'll sacrifice my arm and wrists for almost 300 bones.