AustLit

'When a girl accidentally destroys a magnolia tree, she works as a busker to pay up for a new one. A young man (called Young Ponytail) gives her a mouth organ that, whenever a song is played on it, causes whoever hears it to act to the lyrics. Somehow, the mouth organ is stuck into the girl's mouth and the class blocks their ears and eventually run after the girl, while other people join the chase. Eventually all the people are turned into wood, and Young Ponytail gets the mouth organ out of the girl's mouth.'  (https://en.wikipedia.org/wiki/Unmentionable)