misty orange juice

[XJAWRIGHTX]

once many years ago, when i was about 9 i remember going to a fete where they served cold orange juice with a thick mist that seemed to lingure around the topof the glass, i have searched high and low on the internet, but can not find how to do this.
please, please could anyone that knows tell me the ingredient. i think this would be fab for halloween parties. also am i right by thinking it has something to do with liquid nitrogen