History GenocideBackfire / LiveActionTV

* Uther Pendragon in ''{{Series/Merlin|2008}}'' attempted to kill all the magic users and dragons he could find. Now that he's cleared out all the harmless, innocent ones, the more violent and powerful ones are gunning for his blood. He did manage to kill all the dragons, but decided to keep the last one as an example. When it gets loose, it very nearly burns his city to the ground. And just when you think he's too much of a KarmaHoudini [[spoiler: his daughter Morgana turns out to be magical and kills him.]]
* ''Series/TheOuterLimits1995'': In "To Tell the Truth", after the first wave of colonists arrived on Janus Five, they attempted to place the small and primitive native population into reservations, but the natives proved to be uncooperative. A squad of colonial marines was sent in to kill them, and they later reported that their mission had been accomplished. In spite of this, stories persisted that some of the natives had survived and that they were shapeshifters. [[spoiler: It turned out that these stories were true, and that one of the natives had taken the form of the colony's security chief Montgomery Bennett. Moments before the sun flashed over as Dr. Larry Chambers predicted, Bennett tells the council chairman Franklin Murdock that Chambers' theory that the indigenous lifeforms had evolved to survive the aftereffects of the periodic devastation was correct. He adds that Murdock had been right himself in another respect: the natives planned to use the opportunity to retake control of Janus Five, and the humans' leftover ships and weapons would allow them to repel any further attempts to colonize the planet. The native in Bennett's form is killed, but he is praised by his people for making a HeroicSacrifice so that they could reclaim their home.]]

** A rare heroic example: The Doctor has attempted genocide on the Daleks at least four times. [[JokerImmunity It never takes.]] They just hate him even more now than they did before.
** He did deliberately avoid committing genocide in ''Genesis of the Daleks'', giving as his reason that while the Daleks are indeed evil, omnicidal Space Nazis, a lot of good has come out of people banding together to fight them. That decision sure came back to bite him in the ass.
** After the Doctor supposedly wiped out the Daleks and Time Lords when the Time Lords were prepared to destroy time itself, one more Time Lord managed to escape the War some time before. [[spoiler: Not only is he his (other) arch-enemy, but the rest of the Time Lords use him to escape]].
** The Doctor ended the Time War through the use of some unspecified superweapon, which was supposed to kill all the Daleks and accidentally killed all the Time Lords, but Daleks keep popping up. It becomes clear in the Tenth Doctor's last episode, however, that this is because [[spoiler:''he wasn't just aiming at the Daleks'']].
*** In the 50th anniversary special, it's revealed that rather than destroy the Daleks and the Time Lords [[spoiler:the superweapon in question convinced the Doctor, with help from two of his next incarnations, to hide Gallifrey in a pocket dimension.]] Ultimately, it [[spoiler:would have been the Daleks aiming at themselves.]]

* Near the series finale of ''Series/StarTrekDeepSpaceNine'', the Cardassians have at that point lost all standing with the Dominion and are not much more than unwilling vassals. This leads elements of the [[LaResistance the civilian population]] to subvert the Dominion war effort through acts of sabotage. As a result of one particular incident which nearly cost them a battle, the Female Changeling orders a major Cardassian city to be wiped out by orbital bombardment as an example, and announces that the Dominion will destroy one city for every act of sabotage committed. After hearing this, however, the entire Cardassian fleet does an abrupt HeelFaceTurn ''mid-battle'' in favor of TheFederation instead, as well as getting many Cardassian soldiers on-planet to defect. This in turn prompts the Dominion to to start slaughtering the Cardassians en masse, but since her subordinate proceeds to send out most of their troops stationed at the base to do so, this leaves their installation critically under-guarded when Damar and his crew attack Dominion Headquarters screaming the name of the exterminated city as a battlecry. About half of the force that storms it had been ''guarding'' it up to that point.
** Irony time: the Cardassians used the [[HistoryRepeats same tactics during their earlier Occupation of Bajor]], with the same results (except they were smart enough to not have Bajorans fighting alongside them on the front lines of an interstellar war at the same time).
* ''Series/StarTrekVoyager'' had a variant: The Krenim were going around exterminating entire races from the timestream to make it so their empire never fell. Unfortunately, this was a hit or miss endeavour. Sometimes, it resulted in their empire being at near full strength, others it set them back centuries. But the first ''real'' backfire that happened was that one of the races that helped destroy their empire in the first place also introduced some disease treatment whose absence caused the death of the project lead's wife, and none of the altered timestreams had a cure. Since then, the project lead was desperately searching for a way to fix things for his own selfish reasons. [[spoiler:Ultimately, the problem is solved when Voyager [[RammingAlwaysWorks rams]] the superweapon when it's about to fire, causing it to RetGone ''itself''.]]

** [[spoiler:Arya]] takes a particular delight in pointing this out as [[spoiler:all the males of House Frey die from poisoned wine, annihilating it as a house, as Arya poses as Old Walder Frey via Skinchanging]], saying they should have wiped out ''all'' of the Starks, root and stem, but since they didn't, they are [[KillEmAll where they are now]].