Non-canonical References
- The first "monster" scenario in the tabletop wargame Star Fleet Battles, titled "The Planet Crusher: The Creature that ate Sheboygan III," is based on the planet killer in this episode.
- In the Peter David novel Vendetta it is noted that the theory that the Doomsday Machine originated in another galaxy does not work given the huge amount of fuel required to power the machine. An alternative is presented, theorizing that the device is an early prototype of a machine designed by an advanced race to counter the Borg. The novel further speculates that because it was a prototype, it was never intended for use but was activated when its creators saw their defeat looming. A second, "completed version" of the same machine appears in the novel, this one piloted by a living being who was interfaced with a form of AI based on the minds of its creators. The original Doomsday Machine is reactivated in David's book Before Dishonor, and is piloted by Seven of Nine against a Borg Cube threatening Earth.
- The library computer entry on the Planet Killer in the CD-ROM game Star Trek: Star Fleet Academy mentions a school of thought suggesting that the galactic energy barrier may have been constructed ages ago to keep such planet killers out of the galaxy.
- In addition, other CD-ROM games such as Star Trek: Starfleet Command feature the planet killer as an antagonist.
- The Doomsday Machine is featured as the boss at the end of the Star Trek: 25th Anniversary.
- The concept was used in the FASA Star Trek module "A Doomsday Like Any Other" where the players in the role of USS Fife crew members encounter another Doomsday machine.
- In some Star Trek media, notably comic books, Commodore Decker is portrayed as one of Captain Kirk's mentors and teachers at Starfleet Academy, providing a backstory for their relationship and deepening it.
- In the Star Trek: Phase II fan made episode "In Harm's Way," both Commodore Decker and the planet killer(s) are featured.
- Gene Roddenberry's novelization of Star Trek: The Motion Picture identifies Enterprise Captain Willard Decker as son of the late Commodore Matt Decker.
- In the video game Star Trek Online the player has to defeat a Doomsday Machine in the mission "The Doomsday Device".
- A recycled version of the plot was used in Gene Roddenberry's Andromeda in "Belly of the Beast."
Read more about this topic: The Doomsday Machine (Star Trek: The Original Series)