Sound-producing sweets

Sound producing chocolates are chocolates which when are eaten by a person allows the person to produce a sound similar to any animal or thing. Each chocolate is specific in what sound it will produce. The known sounds are Lion, Dog and a train whistle. These chocolates were seen in the movie prisoner of Azkaban,where the Gryffindor third year boys are seen eating these chocolates including Harry, Ron, Seamus,Neville and Dean in their dormitory.