A leprechaun is a supernatural being in Irish folklore, classed by some as a type of solitary fairy. They are usually depicted as little bearded men, wearing a coat and hat, who partake in mischief. In later times, they have been depicted as shoe-makers who hide a pot of gold at the end of the rainbow. Films, animated cartoons, and advertising have popularised a specific image of leprechauns which bears little resemblance to anything found in the cycles of Irish folklore.

Source: Wikipedia