Video
This is a link to a video of Supercooling water so when you pour it, it forms into slush. 
Im not an expert, but I understand that if you have water in a very smooth-walled container, and cool it evenly, that the water can get below its normal freezing point without crystallizing. It has to do with the lack of points of nucleation due to the smooth container. So when you pour it out of the smooth sided container it freezes. The opposite can be done and the water can be superheated over its normal boiling point, which is very dangerous because when it finally does boil it practically explodes.
Click this link to see superheated water! 
