In this episode of DaveHax he melts the metal Gallium and show how to make a metal lego man out of it.Using Gallium liquid metal and casting Lego style figures and blocks in ice cube moulds. Gallium metal is a solid at room temperature, and turns liquid at around 30°C.
Gallium does not exist elementally in nature, it has to be made. Part of the reason why you cannot just dig the stuff out of the ground is that it has an extremely low melting point (~86°F, 30°C).
A hot sunny day reduce a piece of the stuff into a very scary looking puddle.When put into the fridge, gallium sets an can be molded into different shapes. Take the spoon that you see in the video above.
It looks like a spoon, bang it on a table and it sounds like a spoon, but raise the temperature above 30°C (29.9°C to be precise) and it melts in spectacular fashion.! Fortunately, it is safer to handle than mercury. According to the Department of Energy, as long as you don’t drink or inject the stuff you will be fine.