Liao Wei-Chueh and colleagues at Lite-On Technology designed the Moldable Mouse, made of modeling clay covered with a nylon and polyurethane blend fabric. Like the name implies, the mouse will retain its shape when molded.
This mouse, which on the 2007 Red Dot Award for Design Concept, can be
tailored specifically to an individual's hand shape for that oh, so perfect fit.
I'm guessing that the mouse's potential for office creativity (either that or sexual harrassment) is tremendous: http://www.red-dot.sg/concept/porfolio/06/13pw/R094MM.htm - Thanks Anne!
All modelling clays are dense.
From dense to very dense.
Put your mouse in your hand
now imagine trying to use a mouse that's 10 to 15 times heavier.
There are lighter materials, but they are non deforming gels, which defeats the purpose of a moulded fit.
It's cool anyways, maybe it can be used as one of those carpal tunnel-whatchamacall'em balls...