Ghostwriter is a character that appeared in the episode "Harmony Steals The Show". He is an entertainer and musician who runs the Fly-By-Night Fright Club for ghosts and other spectral entities located within the chasm of an inactive volcano. Recently, his nightclub acts were boring his patrons, who were now demanding to see "live entertainment", and were threatening to go elsewhere if Ghostwriter couldn't provide it. As Ghostwriter looked around for prospective "live entertainers", he noticed Harmony out in the forest playing his trumpet and racking his brain trying to compose an original symphony through which he can impress his fellow Smurfs. Ghostwriter offered to give Harmony an "original" symphony he can claim as his own in exchange for signing a contract, which Harmony hastily signed, not knowing that this would bound him eternally as Ghostwriter's "live entertainer", as he found out after he performed the symphony that night much to the applause of his fellow Smurfs before he disappeared from sight right on stage.

Realizing where Harmony had gotten his "original" symphony, Papa Smurf and his little Smurfs tracked down Ghostwriter to his nightclub, with the village leader demanding for Harmony's release. When Ghostwriter refused, stating that Harmony was now under contract to him, both he and Papa Smurf took the matter before the judge and jury consisting of ghosts and spectral entities to dispute the actual origin of Harmony's "original" symphony which Ghostwriter claimed he had written. As Papa Smurf had his little Smurfs who were part of the village symphony orchestra replay the entire symphony during the trial, the various jurors discovered that it contained pieces from their own symphonies and thus Ghostwriter had been plagiarizing their works. The judge then deemed that Ghostwriter was guilty of perjury and had him sentenced to prison while Harmony was released into Papa Smurf's custody.