The topic of the "Rat King" came up at work today. I guess it's kind of an urban legend where the tails of several rats become entwined and knotted, creating a mass of rats that kind of live as one.
Anyway, that reminded me of the work of David Falconer. Some of his best known work are sculptures created using casts of what must be hundreds of dead mice. I wish I could find more info and pics but they seem to be scarce.