Swiss watchmaker Henri Maillardet created the "Ethiopian caterpillar" in 1820 (or thereabouts) for a wealthy Chinese collector. It's covered in gold and encrusted in jewels and peals. It was sold at Sotheby's in 2010 for $415,215.
From the Oddment Emporium:
When the automaton movement is engaged, the caterpillar crawls realistically, its body moving up and down simulating the undulations of a caterpillar by means of a set of gilt-metal knurled wheels. The automata work is composed of a barrel, cam and two levers all working together to create the crawling motion.