This marks the first time that Ecto-1 is possessed by a ghost.
In The Real Ghostbusters Complete Collection, Volume One's introduction to this episode, Marsha Goodman - Voice and Casting Director - states James Avery is the guest star of the episode.
This was the first episode of the series to go into production.
The ghost Killerwatt received an entry in the 2016 tie-in book "Tobin's Spirit Guide - Official Ghostbusters Edition" on page 56 and 57, where it is identified as a Class VII elemental entity composed of electricity and psychokinetic energy.
The Ghostbusters' case initially involves Stacy's Department Store, which seems to be based on the retail chain, Macy's.