"Kinderlumper" is a song from the episode Der Kinderlumper sung by Dr. Doofenshmirtz. Originally sung by his mother to him, it tells the Drusselsteinian fairy tale of the ferocious Kinderlumper, who takes misbehaving children and puts them in his gundersack. A version presenting the Kinderlumper as a positive figure is partially sung by Roger later in the episode; this version was also taught by their mother. The different versions are meant as another reminder about how much more their mother loved Roger than Heinz.