History Main / MutualKill

** Subverted in the final gunfight of the show. [[spoiler: Raylan gets into a quickdraw duel with Boone. At first it seems like both men manage to get a hit in before dropping. While Raylan got Boone through the chest, Boone's attempt at a headshot resulted in the bullet only grazing Raylan's head. It did destroy his iconic NiceHat, though.]]

** This effect is taken UpToEleven in ''VideoGame/{{Splatoon}}'', where even the basic [[StandardFPSGuns assault-rifle-equivalent weapons]] have projectiles slow enough for this to happen with considerable frequency. This is also what happens if two Roller users collide head-on.

[[quoteright:250:[[Comicbook/TheDeathOfSuperman https://static.tvtropes.org/pmwiki/pub/images/supermandoomsdaykill_5987.jpg]]]]

** the second Mizukage and Muu, the second Tsuchikage, had a [[ArchEnemy long-standing grudge]] which led to them killing each other in a final battle. [[spoiler:After Kabuto resurrects both of them with the impure world resurrection, Mu reminds the Mizukage of this fact, much to the latter's displeasure.]]

* Film/MegaSharkVsGiantOctopus and it's sequels play with this trope like it's their favorite toy:

** Mega Shark vs. Crocosaurus zigzags this as their deaths aren't presented as them succumbing to wounds they've inflicted on each other, but rather the two monsters being so caught up in their fight that they don't notice the undersea volcano erupting beneath them.
** Mega Shark vs. Mecha Shark plays with it in that it's closer to TakingYouWithMe and in that the Mecha Shark isn't technically alive, but rather a manned submarine in the shape of a shark with an AI copilot; after The Mega Shark sinks the Mecha Shark, the surviving crew set the Mecha Shark to self destruct, with the explosion going off right as the Mega Shark comes in for the kill.
** Mega Shark vs. Kolossus plays this similarly to vs. Mecha Shark, with the primary differences being that instead of a self destruct system the Kolossos' power core is overloading and the Kolossus has its own volition; at the climax the Kolossus pulls the Mega Shark beneath the waves and clamps his arms and legs around it until he explodes.

* In ''Videogame/FTLFasterThanLight'', it is possible for the player to kill the FinalBoss while being destroyed at the same time, or even slightly after the player ship is destroyed. It still counts as a victory, since you [[KeystoneArmy crippled the Rebels' command]] and secured a victory for the Federation.

* In the multiplayer of ''Videogame/GrandTheftAutoV'', Players will often find themselves at the mercy of each other's murder, whether it be a mutual stabbing, shooting, or bombing; and sometimes more creative. Mutual kills occur more than often when two players spawn beside one another, face-to-face, and usually end up killing each other simultaneously. An example: Player A drives towards Player B in a truck. Player B opens fire, killing Player A, but not before the truck flattens Player B.

** ''VideoGame/{{Halo 3}}'' has a multiplayer medal for anyone who does this, usually by tossing a grenade right before death.

* Near the end of ''VideoGame/{{Yakuza 4}}'', Katsuragi shoots [[spoiler: Yasuko]] in the back, resulting in a fatal wound. However, before her death, she manages to retaliate by popping a headshot right back at Katsuragi.

[[folder:Web Comics]]

** Mega Shark vs. Kolossus plays this similarly to vs. Mecha Shark, with the primary differences being that instead of a self destruct system the Kolossos' power core is overloading and the Kolossus has its own volition; at the climax the Kolossus pulls the Mega Shark beneath the waves and clamps his arms and lets around it until he explodes.

* ''Literature/{{Carrie}}'': Margaret stabs Carrie and Carrie strikes back, telekinetically giving her mother cardiac arrest. Carrie survives after this exchange long enough to cause [[AlphaBitch Chris Hargensen]] and [[JerkJock Billy Nolan]] to have a fatal car crash before the combination of shock, blood loss from the knife wound, and overstraining her body finishes her. [[Film/{{Carrie}} The movie version]] has Carrie telekinetically crucifying Margaret in a doorway with assorted kitchen implements after Margaret stabs her. Carrie is then finished off by the burning, collapsing house.

* Possible in TabletopGame/BattleTech, as damage is dealt simultaneously, so a mech or tank that's been killed still has the chance to fire back and get a possible kill in return. Especially likely if both units are heavily damaged.
* Can happen in ''TabletopGame/{{Exalted}}'' where combat actions are determined by ticks. if two characters are due to act in the same tick both their actions happen simultaneously and damage and effect caused by the other character take effect only after that characters turn. that way both characters can kill each other at the same time.
* The ''TabletopGame/MagicTheGathering'' card [[https://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=479616 Mutual Destruction]] destroys a creature, but requires you to sacrifice another creature.

* In ''TabletopGame/{{Stratego}}'', this is the official rules' result of attacking an enemy piece that turns out to be the same rank as yours. Many players instead go with a house rule of "attacker wins".
* Can happen if two units with the same Initiative score go toe-to-toe in ''TabletopGame/{{Warhammer 40000}}''. One battle report ended with an Inquisitor Lord and a 13th Company Rune Priest simultaneously smashing each other flat, for example.

** In the backstory, most dragon-on-dragon combat during the Dance of Dragons ended with both dragons dead or mortally injured.
** Per ''Literature/FireAndBlood'', Ser Arryk and Ser Erryk Cargyll killed each other. Either after an Epic Duel lasting more than an hour, where the bystanders don't intervene because they can't tell which Twin is which or after a single stroke by both sides.

* In ''[[Film/ReturnOfTheJedi Star Wars Episode VI: Return of the Jedi]]'', Darth Vader, [[HeelFaceTurn turning back from the dark side]], picks up Emperor Palpatine while he's electrocuting Luke, and [[DisneyVillainDeath throws him into the]] [[TechnicolorDeath main reactor of the Death Star]]. [[HeroicSacrifice However, Vader is fatally electrocuted by Palpatine's lightning in the process]].
* In ''Film/TheRiseOfSkywalker'', Palpatine returns from the dead, but by the end of the movie, he is destroyed by Rey, but the act ends up killing her as well, though Ben revives her shortly after.

This is sometimes TruthInTelevision. With "ai uchi" (mutual killing -- hence the trope name) being a common outcome of samurai duels. Potentially ''any'' duel where [[InertiaIsACruelMistress weapon inertia]] or lag can compensate for attack lag can have "mutual killing" as a normal outcome. It's not unusual either for one party to lethally wound another, only for them to return the favor very quickly before they die (or for both parties to pretty much strike or shoot each other at basically the same time). Quite a few shoot outs and sword duels ended up as blood baths this way. If you're so "lucky" as to be the better combatant, in this case, it may only mean your lethal wound is slighter and you die a slower and more prolonged death. In stories, this is sometimes used for the "winning" character to talk to loved ones or to have a touching character defining moment.

* ''Series/DoctorWho'': "[[Recap/DoctorWhoS36E12TheDoctorFalls The Doctor Falls]]" has an interesting example with [[TheNthDoctor two different versions of the same character]] — [[spoiler:Missy stabs the Harold Saxon version of the Master, so that he'll regenerate into her. He's so angered by her doing this because she's siding with the Doctor that he shoots her when she turns around.]]

* In the first anime of ''Anime/SailorMoon'', the Sailor Guardians trick Cyprine and Ptilol of the Witches 5 into doing this to each other. In the first season's GrandFinale, this takes place thrice. Jupiter unleashes all her lightning energy to kill two of the Doom and Gloom Girls, Venus applies her Crescent Beam directly to the forehead of one of them before succumbing to the injuries the other inflicted on her, and Mars uses her last Fire Soul to kill the last D&G girl standing before she can kill Moon. (And the Senshi ultimately are revived thanks to Usagi's last wish on the Silver Crystal.)

* One episode of ''Series/{{Psych}}'' features the death of the founder of a modelling agency. Shawn's first suspect is the victim's wife...[[SuspectExistenceFailure until she dies during her husband's funeral]]. Then, during the climax, Shawn realized that they had killed each other: the husband had slowly been poisoning his wife (due to her being a bulimic) and [[TimeDelayedDeath ended up killing her postmortem]], and as Shawn figured, the wife had been behind the accident that had killed her husband at the beginning of the episode. Unfortunately, [[InspectorLestrade Lassiter]] is not amused that Shawn called him when there was no one alive to arrest.

** When the hero, Yu-Long, and his supposed rival, Jin-Fu, are engaged in a DuelToTheDeath, they suddenly realized several enemy mooks surrounding them, ready to finish off the survivor, under the villainess Chien-Ying's instructions. So they instead pretend to thrush their swords into each other's guts and keel over, PlayingPossum... and as soon as the mooks come over to investigate, Yu-Long and Jin-Fu quickly lerap to their feet and starts taking names.

* A man fighting alongside Jackie in ''Drunken Master II'' manages to dispatch many mooks ''with an axe in his back''.

* ''Series/{{Hanna}}'': Marissa and Stanton, her father, end up killing each other in the finale.

* ''Fanfic/CheatingDeathThoseThatLived:''

** During the 75th Hunger Games, [[spoiler:Skinner Alceto and the mutt known as "The Beast" kill each other]].