* ActingForTwo: Kira and Miles & their MirrorUniverse counterparts. Also [[http://www.youtube.com/watch?v=bCmQg6VkQ4A Bashir]] in "Doctor Bashir, I Presume?"
** Creator/JeffreyCombs, playing clones of the same character, gets to play a good and evil (ie. normal) version of Weyoun arguing over a com-link; he also played the Ferengi character Brunt. Combs always wanted to appear as both characters in a single scene, but never got the chance. He did, at least, get to play both characters in the same episode, Season Seven's "The Dogs of War". Combs played a third character, a holosuite guest, before landing a semi-regular gig on the series.
* ActorAllusion:
** Siddig was considered for the lead role because the producers mistakenly took his old age makeup for his real appearance. This is referenced in "Distant Voices" in which Bashir rapidly ages from a silver fox to a doddering geezer.
** O'Brien finds himself 'typecast' as the hitman Falcon in Bashir's spy holoprogram. Whether or not this was intentional, it mirrors Colm Meaney's pre-''Star Trek'' [[TypeCasting typecasting]] as the same ex-IRA bad guy he plays in every film (see ''Film/UnderSiege'').
** In "The Ship", O'Brien waxes poetic about the mountains of Ireland, but another character reminds him Ireland only has hills. Colm Meany starred in the film ''The Englishman who Went Up a Hill (But Came Down a Mountain)'' about a Welsh village that insists its hill is a mountain.
** Creator/JeffreyCombs as Weyoun, who [[ReAnimator had a background in "creative genetics"]]. ("Treachery, Faith, and the Great River")
** A HatePlague causes Garak to go nuts and start killing people in "Empok Nor," much like his serial killer villain in ''DirtyHarry''. Robinson was a little nonplussed about the script, having endured years of people [[IAmNotSpock mistaking him for a total maniac in real life]], but chose to grin and bear it.
** In the episode where [[AndYouWereThere Quark is a writer for a 1950's sci-fi magazine]], there's a note from the editor on his desk [[ItWillNeverCatchOn rejecting the idea of a story about a cheerleader who kills vampires]]. Armin Shimerman was playing Principal Snyder in ''Series/BuffyTheVampireSlayer'' at the time.
* ActorSharedBackground:
** Like his character, Andrew Robinson is claustrophobic. He had trouble wearing the prosthetic early on. Garak also spoke of posing as a gardener while conducting surveillance on Romulus. His stint at the Cardassian Embassy coincided with a number of mysterious deaths that year, including a Romulan proconsul who was found poisoned. This is an in-joke by Andrew Robinson, who is passionate about gardening in real life but hasn't murdered anyone. (That we know of.)
** When Kira is complaining about how she feels being pregnant with the O'Brian's baby she says "This is YOUR fault!" to Dr. Bashir. Nana Visitor was [[RealLifeWritesThePlot really pregnant]] with Alexander Siddig's child.
* AluminumChristmasTrees: "Far Beyond The Stars" seems to be a full episode about ECComics's ''[[http://asylums.insanejournal.com/scans_daily/54803.html Judgment Day]]'' (printed around the same time this story is set), which killed the magazine when the publishers and editorial disagreed over having the hero be black.
* AuthorAppeal: Ira Steven Behr asked James Darren and IggyPop to play a role because he was a fan of their work. Both ended up getting a LoveItOrHateIt reaction from the fans.
* BrokenBase: If purists were uneasy with TNG, that ''hated'' [=DS9=]. After all, ''"To boldly sit"'' is not exactly a fitting epitaph for Gene Roddenberry. His widow, Majel, wrote an open letter to the fanmag ''Star Trek: Communicator'' condemning the show's portrayals of war, something [[http://www.lcarscom.net/rdm1000118.htm Ron D. Moore]] joked about in an interview. Even Executive Producer [[http://www.startrek.com/article/rick-berman-looks-back-at-18-years-of-trek-part-2 Rick Berman]] admitted he's unhappy with the direction the series took -- but he mostly let Ira Behr do what he wanted, as Rick already had his hands full with VOY and the TNG films.
* {{Defictionalization}}: Beyond the examples shared with other Trek media, the scifi novel "Far Beyond the Stars" from the episode of the same name was later written and published.
* DirectedByCastMember: Avery Brooks, Rene Auberjonois, Michael Dorn, Alexander Siddig and even guest stars Andrew Robinson and Jonathan Frakes get at least one shot behind the camera. And [=LeVar=] Burton, who appeared in ''[[Series/StarTrekTheNextGeneration The Next Generation]]'', took a spin as well. In fact, Burton was the fifth most prolific director on the series, while Brooks and Auberjonois share sixth place.
* DuelingShows: With ''Series/BabylonFive'' during its '94-'95 run. [[Creator/JMichaelStraczynski JMS]] claimed (with some justice) that Paramount stole his story treatment, and it got pretty ugly in spots.
** A (barely) oblique reference was made to this on B5. In one episode, a gift shop is set up on the station. One of the characters loudly derides this idea, saying "This isn't some deep-space franchise! This station is ''about'' something!" It should be noted that the writer of this episode, PeterDavid, has written several ''Franchise/StarTrek'' novels. (When he wrote that line into the B5 script, it was with the expectation that JMS and friends would change it, if only to a more subtle jab, before shooting; upon learning that the line was filmed and broadcast verbatim, David remarked to JMS that "...you people are dangerous over there, aren't you?")
** The ''Deep Space Nine'' writers weren't above including their own subtle jabs at B5. One episode featured Bashir having to chaperone a cadre of Ambassadors visiting the station and putting up with all the crap that comes with it. According to JMS, the Writers of [=DS=]9 actually liked [=B5=]. The '''producers''', not so much.
* ExecutiveVeto::
** Andrew Robinson explicitly played Garak as bisexual or ominisexual in his first scene with Dr. Bashir. Writer Robert Hewitt-Wolfe corroborated this, adding that Bashir was supposed to be oblivious to his advances. This plot thread was swiftly bundled out of sight by Paramount, though it doesn't ''entirely'' go away (at least as far as Garak's mannerisms went.)
** In "Facets", Sisko willingly allows himself to be possessed by Joran Dax for a short term. Avery Brooks was required to do shoot this scene twice. The reason? Brooks' performance was way too scary for a PG show.
* FanNickname:
** Kai Opaka was called "Deep Space Nun" during the first season but was PutOnABus midway through the season.
** Thanks to reviewer SFDebris, the practice of calling the ''Defiant'' the ''USS Ben Sisko's Motherfucking Pimp Hand,'' is slowly catching on.
* FollowTheLeader: [=DS9=] had trouble finding its feet initially, leaning on unresolved arcs from TNG and more or less sticking to its episodic format (not unlike VOY & ENT). As ''BabylonFive'' began to makes waves with its much-hyped, five-year arc, the Dominion War was shortly introduced. The two would remain DuelingShows for the remainder of their respective runs, with [=B5=] wrapping up in 1998 (a year before [=DS9=]).
* [[GermansLoveDavidHasselhoff Germans Love the Dax Symbiont]]: After taking an extended break to raise her son, Terry Farrell finally started making the rounds at conventions. When she appeared at [=FedCon XIX=] in Bonn, Germany (the largest gathering in the world) in 2010, the standing ovation [[https://www.youtube.com/watch?v=PbceUaHkzyM#t=185s lasted for over three minutes]] and moved her to tears.
* HeyItsThatGuy:
** Michael J. Anderson (the "Man From Another Place" of ''Twin Peaks'' fame) plays Rumpelstiltskin in an early episode. ("If Wishes Were Horses") He was originally supposed to be a leprechaun who bothers O'Brien, until the less-than-amused Colm Meany made the writers change it
** Iggy Pop as a Vorta in "The Magnificent Ferengi". Ira Behr lamented casting one of his idols (and a legendarily rowdy rocker) as such a monotone creature.
** [[OneFlewOverTheCuckoosNest Nurse Ratched]] is now a spiritual leader??
** [[Series/BabylonFive General Hague]] as Admiral Leyton in "Homefront" and "Paradise Lost". Pretty ironic, all things considered.
*** In fact, the reason that Hague was killed off in B5 was because of a scheduling conflict where he was shooting over on Deep Space 9.
** [[{{Seinfeld}} Babu Bhatt]] as Dr. Bashir's father.
*** [[TheBigBangTheory Raj Koothrapali's]] gynecologist dad, a [[Film/{{Employee of the Month}} Super Club associate]] and [[Film/AustinPowers a UN representative]], too? Bashir's dad *has* had a lot of jobs.
** J.G. Hertzler, most well-known among ''Deep Space Nine'' fans for playing Martok, also played Sisko's commanding officer, the Vulcan captain of the ''U.S.S. Saratoga'' in the pilot episode "Emissary". He also later played changeling Laas in Season 7's "Chimera".
*** Which means he played Changelings twice, no? Several times in the guise of Martok, and once as Laas.
** [[Film/ThePrincessBride PRINCE HUMPERDINCK]] as Martus Mazur, Quark's one-episode commercial rival in the Season 2 episode "Rivals". Sadly, he does not share a scene with Grand Nagus Vizzizni.
*** Now if only they could just have put ''Zek'' in that episode somehow. Surely they could have found a way.
** Bill Mumy, best known as Lennier in rival show ''[[Series/BabylonFive Babylon 5]]'', or Will Robinson of ''LostInSpace'', appears in "The Siege of AR-558". His one stipulation for crossing over was that he '''not''' have to wear any more prosthetics.
** Mumy is the only [=B5=] cast member to think that far ahead; both Andreas Katsulas (Tomalak on TNG) and Mary Kay Adams (Lady Grilka on [=DS9=]) were stuck with rubber foreheads.
** Speaking of B5: Captain Kate Lockley guest-starred as a Cardassian engineer who butts heads with O'Brien. (She later tried bumping something else, but alas, he's happily married.)
** Melora is Dr. Grace Holloway from the '90s ''Doctor Who'' [[Recap/DoctorWhoTVMTheTVMovie TV movie]].
** Mixing in with HeyItsThatVoice is Martus from [[StarTrekDeepSpaceNineS02E11Rivals "Rivals"]]. Played by Chris Sarandon, AKA [[Film/TheNightmareBeforeChristmas Jack Skellington]].
** [[Film/StarTrekIVTheVoyageHome Admiral]] [[Film/StarTrekVITheUndiscoveredCountry Cartwright]] is Ben Sisko's dad.
* {{Hey Its That Voice}}: Jeffrey Combs would later become the voice of [[{{Justice League Unlimited}} The Question]], as well as [[WesternAnimation/TransformersPrime Rachet]], [[WesternAnimation/AvengersEarthsMightiestHeroes The Leader]], and [[WesternAnimation/TeenageMutantNinjaTurtles2012 the Rat King]].
** Michael Ansara, AKA [[WesternAnimation/BatmanTheAnimatedSeries Mr. Freeze]] reprises his role as Kang (TOS) in "Blood Oath".
* RetroactiveRecognition:
** Two actors from ''Series/BreakingBad'' appear at the beginning and end of the series; Jonathan Banks (''BB'''s Mike Ehrmantraut) appears as an exiled criminal in Season One's "Battle Lines", while Raymond Cruz (Tuco Salamanca) plays a PTSD-suffering soldier in Season Seven's "The Siege of AR-558".
** One of Bashir's savants went on to play Divatox on ''Series/PowerRangersTurbo.''
* RomanceOnTheSet: Alexander Siddig (Bashir) and Nana Visitor (Kira) got together and had a son, with Visitor's pregnancy [[RealLifeWritesThePlot being written into the show]]. They married the next year and divorced in 2001. Which leads to rather hilarious in joke in the episode where Kira says "This is all your fault!" to Bashir during an argument, since (in universe) he was the one that did the fetal transplant from Keiko to Kira. Funnier still because [[BizarreAlienBiology Bajoran labor is usually quiet and easy]].
* ScienceMarchesOn: Near the end of [=DS=]9, Dr. Bashir asks Odo to donate part of his natural goo to help figure out how to grow new organs. Come the early 21st Century, and humans have nearly perfected the ability to grow organs in a lab - not, admittedly, organs that can change to become the one that is required by an impending surgical procedure (which is what Bashir was aiming for).
** Bashir wanted it to help find a way to grow organs on the battlefield - it's on thing to grow a new organ for a lung transplant when someone has been ill for a couple of months, but it's hard to know how many lungs, hearts, etc to have on standby on a battlefield, nor do you often have the time to grow them as the patient could die before they are fully mature.
* ThrowItIn: A joking reference by Odo to Adm. Ross as "Bill" in the first episode of season 7 was taken literally by the writing staff, resulting in his canonical first name. (As well as confusion for sharp-eyed viewers, as his office nameplate had previously established his first name to be Cliff!)
* VindicatedByHistory: It goes without saying that [=DS9=] was never in the same league of acclaim as TOS, TNG, or even VOY. (Just look at the merchandising.) On the other hand, time has arguably been kinder to [=DS9=] than its sister show, ''Voyager''. Back in '98 and '99, Nana Visitor was giving interviews declaring that one day, fans would come around to liking the show. And voilą: fifteen years later, it's finally caught on -- thanks to much less competition, on-demand streaming, and Moore's later success on ''[[Series/BattlestarGalacticaReimagined Battlestar Balactica]]''.
-->'''[[https://www.youtube.com/watch?v=z_nenMkNu5o#t=140s Visitor]]:''' I remember sitting with Armin Shimerman on set and going, 'They don't really get us', and they didn't at the time. But we said, y'know, 10-20 years, they'll get it.
* WagTheDirector: If you study DeepSpaceNine's behind-the-scenes' trivia, you realize a good part of the regular and recurring actors became very involved with their character. Especially people like Andrew Robinson and J.G. Hertzler, who each wrote a whole novel about their character, Garak and Martok; or Nana Visitor, who met with the writers whenever she felt a scene was wrong about Kira. Another big name actor, Rene Auberjonois, consulted regularly with the writers (requesting a new uniform for Odo, etc.), though he was a ''little'' more subdued--even if he didn't particularly care for this or that plot development:
-->'''Ira Behr''': Being the pro that he was, he sucked in whatever dismay he was feeling--though I still got some of those vibes. He didn't do a screaming, "I won't do it, I won't play it! No no no!"
** Visitor flat-out vetoed a romance with Gul Dukat, which had been building on mutual attraction from around the time of "The Maquis." The showrunners acquiesced, but later got their revenge by revealing Kira's mother to be one of Dukat's old mistresses. D'oh.
** Re the shocking twist finale ("What You Leave Behind") of Sisko [[spoiler:dying in the Fire Caves and becoming a Prophet]], Avery Brooks was firm: ''Hell'' no, especially given the [[UnfortunateImplications implication]] of an African-American male ditching his wife and newborn child. The writers suddenly saw his point, and the ending was rewritten to make Sisko's departure more ambiguous.
** Out of all the cast members, Michael Dorn probably had the most pull. He wasn't interested in reprising his old role, but the showrunners were so desperate to have Worf cross over that they bent over backwards to make him happy. No longer would Worf be the big guy who got tossed around cargo holds! Interestingly, he was not involved in the decision to pair Worf with Jadzia, though he obviously made no demur.
** Siddig wasn't too happy about his character being retconned into an Augment. He interpreted it as Behr/Berman et al. attempting to squeeze him into a "Data" role without consulting him, and responded by deliberately reading long equations and statistics in a drowsy, non-eloquent manner. The Augment stuff quickly faded into into the background and became all but irrelevant.
* WhatCouldHaveBeen:
** The producers briefly toyed with the idea of making [=DS9=] a land-based show (as opposed to space station-based one), but the costs of location shooting proved prohibitive.
** Much like with VOY's premise, ideas were pitched around on how to [[ResetButton hard reset]] [=DS9=] into a traditional ''Star Trek'' show if the fans didn't take to it. This might be why "Emissary" established that the station is capable of reducing its mass in order to move; according to Behr, it was suggested that the crew strap engines onto [=DS9=] and [[http://trekcore.com/blog/2013/05/exclusive-ron-moore-ira-steven-behr-interview-part-ii/ fly into the wormhole.]]
** Michelle Forbes, playing the part of Ensign Ro, was originally supposed to be ''Deep Space Nine'''s token Bajoran in the cast. Forbes didn't want to commit to a full television series, so the new character of Major Kira was created. Ro would end up serving as the station's chief of security in the [[StarTrekDeepSpaceNineRelaunch relaunch novels]], however.
** Contrary to popular belief, Sisko was not written to be black. The producers auditioned actors from all over, including (according to Brooks) one from Prague. In fact, Alexander Siddig originally tried out for the part of Sisko(!), but was turned down for being too young.
** More understandably, Andrew Robinson tried out for the part of Odo.
** Bashir, the [[TheScrappy Scrappy]] in residence, was nearly axed from the show numerous times. Siddig didn't even know about this until well into the fourth year.
** In the TNG crossover "Birthright", Dax was slated to film some scenes on the ''Enterprise-D'' set with Data, but a scheduling conflict dashed that idea. Bashir went over in her place. The episode she filmed instead? The execrable "Move Along Home". According to Terry Farrell (a lifelong Trekkie), she "cried."
** Melora (from the eponymous season 2 episode) was meant to be the permanent science officer, but was replaced with Dax and reused as a one-off guest character -- thus cheating poor Bashir out of a romantic interest yet again.
** Robert Hewitt Wolfe planned to end "Second Skin" on an AmbiguousCloneEnding, with Bashir unable to determine whether Kira [[YouAreWhatYouHate is actually a Cardassian]]. This left open the possibility that Kira was unknowingly a Cardassian agent all along, and that the Obsidian Order had been telling the truth.
** When the Dominion invaded Federation space, Vulcan was pitched as one of the occupied planets. Ron Moore commented that Vulcan "carried too much weight," so [[CListFodder Betazed got thrown overboard]] instead. Ironically, J.J. Abrams would happily blow Vulcan to smithereens in [[Film/StarTrek the 2009 movie]]. In an even more ironic decision, he blew Vulcan to smithereens for ''precisely'' the same reason that Ron Moore ''didn't'' have it occupied- it showed how serious things were, and that things were not going to be the same again.
** The writers considered a Kira/Dukat FoeYay scenario (season 4's "Indiscretion", introducing Dukat's half-Bajoran [[MoralityPet love child Ziyal]], is artifact to where things may have headed). However, Nana Visitor (Kira) [[NoYay flatly refused to do anything of the sort]], pointing out that he '''was''' guilty of the brutal occupation and near-genocide of Kira's species. Instead, the storyline was given to Kira's mother Meru as Dukat's "comfort woman" during the occupation in "Wrongs Darker Than Death Or Night." Similar to Michelle Forbes inadvertently causing the creation of Kira, this storyline probably worked out better for Kira's character.
** Bashir's secret agent holo-program was intended to be a series staple, like TNG's Dixon Hill. Unfortunately, the people at MGM took it for an unauthorized Bond parody. Wonder where they got that idea, with names like Honey Bear and Mona Luvsitt?
** Ira Behr tried (and failed) to get a Vic Fontaine-like character onto the show for years. Frank Sinatra Jr. was approached first, but as he would be playing a Rat Packer jazz artist (and thus be misconstrued for [[Music/FrankSinatra his father]]), he wasn't interested in playing that type of character. Robert Goulet and Tom Jones also turned the part down.
** While "Trials and Tribble-ations" is regarded as one of the best episodes of the series and a fitting 30th Anniversary for the franchise, there were numerous other ideas which were tossed around. One was the return of EnfantTerrible Charles Evans from the TOS episode "Charlie X", most likely seeking revenge in a manner similar to Barry Waddle. Another was having the Deep Space Nine crew visit the mobster planet from "A Piece of the Action", where they find that the inhabitants have [[YouAreTheNewTrend gone on to emulate Starfleet]] as a commentary on ''Star Trek'' fandom.
** Speaking of "Trials and Tribble-ations," Dennis [=McCarthy=] originally wanted to re-record Jerry Fielding's kitschy score for "The Trouble With Tribbles" to go with the new episode's other recreations, but Rick Berman overruled him and demanded he write an original score. (Although he claims it wasn't in the budget.)
** The writers originally toyed with the idea of killing off Jadzia Dax in the Season 6 episode "Change of Heart" rather than in "Tears of the Prophets", the season finale. The idea was that Jadzia would manage to convince Worf to continue their mission without her and leave her behind, in which case she certainly would have died. Worf would then have had even ''more'' angst than he ended up with to work through in the final season, having lost his wife out of choosing his career over her. Terry Farrell (Jadzia) was on board with it, but they ended up not going through with the idea.
** The decision to ship Kira to Cardassia had a domino effect on the rest of the seventh season. Garak went along as backup, and Ira Behr didn't want to split Kira and Odo up, so Odo went, too. Originally, Odo was going to spearhead the search for a cure for the Changeling plague, culminating in a reunion with his "father" Dr. Mora [[ArchnemesisDad who was actually responsible for engineering the virus as a weapon]]. The writers knew they would never have time to do this storyline justice, so Bashir and O'Brien went looking for a cure instead.
** The cast hoped there would be a movie spinoff at some point (the [=TN=]G films still being successful at the time of [=DS=]9 ending) but the failure of ''Nemesis'' put paid to that idea. Any hopes of resurrecting the project would seem over - the actors have all seriously aged out of the roles (at the time of writing, it's been fourteen years since the show went off the air). The 2006 auction at Christies where a huge number of props (including the "hero" model of the station itself), costumes and other items from the series were sold off made it even less likely and the 2009 reboot of the entire ''Star Trek'' franchise would seem to be the final nail in the coffin. One person who doesn't seem to mind is Alexander Siddig, who believes [=DS9=] deserved to be '[[BritishBrevity put to bed]]' and can stand on its own merits. Nana Visitor, however, thought the show had a lot more mileage left. (Mostly, though, she wishes she could have had one year of [[http://www.startrek.com/article/ds9s-major-kira-nerys-nana-visitor-part-2 running the station!]])
* WordOfDante: Barry Jenner was mostly winging it while playing the Admiral Ross character. He decided that Ross was a conflicted family man whose son enlisted and died in Starfleet, and that (internally, at least) he regrets the blackguard things he does to preserve the Federation.
* WordOfGay: Andrew Robinson has commented in multiple interviews that he considered Garak "omnisexual," and also strongly implied it in the character book he wrote. Robert Hewitt Wolfe has [[http://www.exisle.net/mb/index.php?showtopic=38718&st=160&p=857040&#entry857040 stated]] that he wrote Garak to be attracted to Bashir, but Bashir [[ObliviousToLove never realized this]].
* WordOfGod: Ron Moore stated that although the background check in "Doctor Bashir, I Presume?" ended up marring Bashir's exemplary reputation, this didn't preclude him from being the new template for the Emergency Medical Hologram and -- despite Dr. Zimmerman's complaints -- he did actually end up being selected. Therefore fans assume that either the (unseen) EMH Mark III or Mark IV was based on Bashir.

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!!This series [[ImageSource provides the page image]] for:

* BaldBlackLeaderGuy
* EvolutionaryRetcon (right half)
* RubberForeheadAliens
* SpaceStation
* TuxedoAndMartini

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