Cotton candy, also known as fairy floss and candy floss, is a spun sugar confection that resembles cotton. It usually contains small amounts of flavoring or food coloring.
It is made by heating and liquefying sugar, and spinning it centrifugally through minute holes, causing it to rapidly cool and re-solidify into fine strands. It is often sold at fairs, circuses, carnivals, and festivals, served in a plastic bag, on a stick, or on a paper cone.
Info and image from Wikipedia