Theo Gray (featured previously at Neatorama) cast this fish out of a metal you rarely see made into sculpture -mercury! To keep the shape, he had to cool it to –320°F (-212°C) with liquid nitrogen. When mercury is cooled that much, it acts like tin or other metals we are more familiar with. http://www.popsci.com/mercuryfish -via Boing Boing
Liquid nitrogen is pretty expensive and vaporizes really fast due to the much higher ambient temperature.
Kelly - HILARIOUS!