The Pied Piper
The Pied Piper was an energy entity originaly from the Jeggorabax Cluster, a region known to house beings feeding on emotions. The Pied Piper manifested a need for fear in order to break loose from a piece of rock it was bound to, known as the Weserbergland Meteorite.
The entity crashed to Earth in the Weserbergland Mountains in Lower Saxony in 1283, and by 1284 had broken loose from the meteorite by feeding on the local inhabitants' fear of the plague. Its first major act was to take the children from the city of Hamelin in order to illicit fear from their parents; an act that made it known as the Pied Piper.
Over the next seven hundred years, he continued to abduct children in order to create fear. One notable stint was an eight year period between 1932 and 1940, in America, as "Odd Bob the Clown". It is also implied Odd Bob was responsible for originating Sarah Jane Smith's fear of clowns.
In 2009 he set up Spellman's Magical Museum of the Circus in London in order to steal children from the city. This was made possible by the fact that the Weserbergland Meteorite was on loan to the nearby Pharos Institute. (SJA: The Day of the Clown)
