S4·E3 The Pied Piper of Hamelin

Eric Idle plays a wandering piper who is hired by a selfish mayor to rid his town of rats. The piper is good to his word and leads the rats to a watery grave.However when he asks for payment the mayor reneges, thus causing the piper tp play his pipe for an alternate result -- this time leading all the children out of Hamelin never to be seen again.