A spin-off was planned starring Ron Palillo titled "Horshack". The show was to feature Arnold Horshack and his family. Episode #2.19 "There Goes Number 5" served as the pilot for the proposed series but the show never materialized.
Horshack's mother is played by Ellen Travolta, who is the real life sister of John Travolta. Uncle Harry Orshack is played by James Komack, the show's executive producer.
Andrea McArdle, who played Horshack's little sister, opened on Broadway just over two months later as the title role in the original Broadway cast of Annie.
Ellen Travolta, who plays Arnold Horshack's mom, is only 10 years older than Ron Palillo (Horshack).
Alternate title: "Whatever Happened to Arnold, Part 2."