"Out they scampered from doors, windows, and gutters, rats of every size, all after the piper." -The Pied Piper of Hamelin
The Pied Piper of Hamelin is the story of a rat catcher hired by the town of Hamlin to lure rats away with his magic pipe. When the Piper fulfills his duty and the citizens refuse to pay for his service, he retaliates by turning his magic on their children, leading them away as he had the rats. The story of the Pied Piper may actually reflect a historical event in which the town of Hamelin lost its children. Theories have been proposed suggesting that the Pied Piper is a symbol of the children's death by plague or catastrophe.
In "Danse Macabre", the bullied teen, Roddy Geiger, takes on the symbolic role of the Pied Piper of Hamelin. He decides to get revenge against the people who cast him and his father out of society, focusing on the children that bully him at school. Like the Piper, Roddy has the ability to control rats with his musical talent, though he uses that skill for a different purpose.
"Rats! They fought the dogs, and killed the cats..."
There is less in common between "The Rat King" and The Pied Piper of Hamelin than there was in "Danse Macabre", but the symbolism of the quote is captured well in the episode, as a group of Reinigen, Wesen who have historically been harassed by Klaustreichs in what is known as Reini-bashing, are able to become the aggressors in the feud and seek revenge upon some unfortunate "cats." They are able to take advantage of an ability unique to Reinigen, though this time, it is far from being a musical skill.
- The quote above for the Reinigen is taken not from the Brothers Grimm version, but from Robert Browning's 303 line poem (published in his 1842 "Dramatic Lyrics"), probably the best known version of the tale in Britain.