Development
Development of Issue #20 was publicly documented by the creative team over several months. On May 22, 2014, Tristan Jones previewed his subscription cover, depicting a scene from The Real Ghostbusters' end credits. On June 18, 2014, Jones confirmed the issue was also the series finale. IDW Publishing formally confirmed the end of the ongoing series on June 19, 2014, with quotes from the crew.
Erik Burnham revealed on June 20, 2014 that he was scripting Issue #20, and confirmed on June 24 that every available page would be used to tell the story. He completed a first draft on June 28, 2014, after finishing nine pages on June 27. On July 18, Burnham announced that Tom Waltz, Dan Schoening, and Luis Delgado had all read and approved the script. By August 18, Dan Schoening announced he had finished the issue, noting he had penciled 686 pages across 36 issues over the course of the run.
A cover, credits, and five-page preview were posted on September 18, 2014. The issue went on sale September 24, 2014.
In a post-release conversation on October 7, 2014, Burnham revealed he had learned the series was ending while he was roughly halfway through writing Issue #16. He also clarified that Egon Spengler's line about forced delusion was deliberately open to interpretation, and that he rewrote it slightly for the Volume 9 trade. On September 25, Burnham confirmed Jenny Moran's absence in the epilogue was an oversight and that she would be mentioned in the Volume 9 trade.
Covers
The regular cover was drawn by Dan Schoening with colors by Luis Antonio Delgado. It is a large ensemble piece featuring Ecto-1b; the Ghost Smashers (Jenny Moran, Dani Shpak, and Lou Kamaka) in their new Volume 2 Issue #17 jumpsuits; Walter Peck; the Chicago Ghostbusters, Ron Alexander and the Rookie; Dana Barrett; Louis Tully; Kylie Griffin with Pagan and Tobin's Spirit Guide; Slimer; Special Agent Melanie Ortiz; Egon Spengler; and Winston Zeddemore, Peter Venkman, Ray Stantz, and Janine Melnitz.
Subscription covers were contributed by Tristan Jones (the Real Ghostbusters end-credits homage, confirmed as featuring Slimer), Esther Sanz, and Roberto Goiriz. Tristan Jones posted a work-in-progress of his cover on July 28, 2014, a finished unlettered version on August 12, and confirmed the Slimer art was the subscription cover on August 13.
Trivia
- Egon's dialogue about forced delusion on page 19 is meant to be open to interpretation; Burnham rewrote it slightly for Volume 9.
- The storage room scene on page 3 is an extended homage to the Carl Spackler scenes in "Caddyshack" (starring Bill Murray): the arrangement of lawn tools on the wall, the white cap on the door, and explosive gopher decoys all mirror the film. Other easter eggs in the room include a Super Bass-O-Matic '76 blender from a Saturday Night Live sketch by Dan Aykroyd, a Zalinsky brand tool box referencing the film "Tommy Boy" (in which Dan Aykroyd played Zalinsky), a canister of rocket fuel from the Slimer! episode "Go-pher It," Egon's Field Projector from Extreme Ghostbusters episode "Killjoys," and a KPPX sticker referencing the film "Airheads," which included Ernie Hudson and Harold Ramis.
- Page 4 shows Winston wearing the Good's Baseball Team T-shirt from The Real Ghostbusters episode "Night Game."
- Page 6 references Dan Aykroyd's original Ghostbusters script, where the storage facility was located in a deserted Sunoco station in northern New Jersey rather than the Firehouse.
- The final page with Slimer flying toward the viewer (page 21) was a last-minute addition. Luis Delgado was away for the weekend and did not know about it; only color flatter Anna Chher assisted Dan Schoening with coloring that page.
- Page 22's group shot is a nod to the ending of the first title sequence of The Real Ghostbusters.
- The closing scene on page 26 is a homage to the Ray Parker Jr. "Ghostbusters" music video. The storefront display on page 20 homages a scene from the film "Mannequin." Background pedestrians on page 20 include cameos by Tom Waltz, Erik Burnham, Tristan Jones, Luis Antonio Delgado (leaning against his Jeep named "Amelia" after Amelia Pond from "Doctor Who"), Mork and Mindy from the ABC series, the Men in Black (Agents J and K), and Elvis Presley (using a design from an unused subscription cover for X-Files Conspiracy: Ghostbusters). Casey and Jean Kasem also appear with their backs to the reader.
- A TMNT/Ghostbusters Issue #1 (page 10) follow-up revealed that the ghost captured at Saks Fifth Avenue at the end of this issue was the Subway Ghost from the original Ghostbusters film.
- Winston's sacrifice, in which Tiamat erases the world's memory of his marriage to Tiyah Clarke, leaving only Winston to remember it, is revisited in Ghostbusters: Crossing Over issues #3, #4, #6, and #8, as well as on the What Came Before page of Crossing Over #8 and in Tiamat's bio in the 34th Crossing Over Virtual Trading Card (released June 14, 2018).
- The page 17 error in which the word balloons between Ellen Gold and the Crybaby Ghost are switched was corrected in the Volume 9 trade paperback.
- Peter's "photographer from Queens" line on page 19 is a nod to Marvel Comics' Peter Parker/Spider-Man and the "One More Day" story arc, a parallel to Winston's situation.
- The mention of Portland on page 19 references the television series "Grimm," in which the lead character's girlfriend had her memories of him removed.
- Issue #20 is referenced on page 27 of Ghostbusters: Funko Universe and on page 8 of Ghostbusters 101 #3.
