What to do when you've made an enemy on your own side? Good thing there is a convenient battle coming up... What's one more casualty between friends? The coroner will never know the difference.
Shoot the guy yourself or push him into enemy fire, it makes little difference. Nobody's going to check. That annoying squadmate or sergeant is dead, and you can now resume shooting the enemy like nothing wrong happened. Even if someone recognizes that it was your side's ammunition, Friend or Foe might have happened; even if someone knows you shot him, you can feign bewilderment, claiming in a Friend or Foe situation you made a terrible but understandable mistake — sometimes.
As you might imagine, this is Truth in Television. The military even has a name for it that stems from the use of a fragmentation grenade to kill someone on one's own side of the conflict: "fragging" (which has since become a part of the gamer's lexicon after its use in Doom's popular Deathmatch mode). This originally referred to the specific act of throwing a fragmentation grenadenote because a fired rifle or pistol round can be used to identify the weapon from which it was fired, and by extension the guilty party, whereas shrapnel cannot into the offending officer's tent, but soon spread to all methods. Sometimes even a junior officer, concerned of senseless waste of his men, would eliminate a glory-hungry or inefficient senior officer to save his unit.
Contrast Trial by Friendly Fire, which is about the grisly mathematics of deciding when it's safe to risk accidental friendly fire in order to hit an enemy.
The Team Killer is a character (or player) who engages in Unfriendly Fire. See also The Uriah Gambit for purposely sending an underling to his death. A video game's rules on the issue sometimes result in Friendly Fireproof or a Nonstandard Game Over.
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Anime and Manga
Guts from the Berserk manga did this when he was only eight years old. He was raped by a pederast soldier named Donovan after his adoptive father Gambino sold him to the mercenary for three silver coins. Guts took violent revenge during the very next battle, shooting Donovan in the back with a crossbow and then laying into him with his sword, demanding to know who had sold him to him. Guts did not believe Donovan's final confession that it was Gambino who sold him until the fateful night when Gambino, who lost his leg to a cannonball during the battle in question, got drunk, confessed to the deed and then tried to murder him.
In Macross Frontier, Mikhail's sister killed her commander with friendly fire, but because they were lovers and he had just recently dumped her, some suspected she did it on purpose as revenge. The series never reveals the truth, but obviously Mikhail thinks his sister was innocent.
While they haven't exactly made an enemy of him, the World Government in One Piece decides that Gekko Moriah is too weak to represent them through the Shichibukai; after the Whitebeard War they try to kill him, intending to use the excuse that he died in the war.
Occurs in volume four of The Walking Dead, "The Heart's Desire". Rick shoots Dexter, a prison inmate who stated his intent to forcibly evict Rick and his group from the well-stocked and spacious prison as soon as the zombie attack was quelled. It was under the cover of a heated, surprise zombie attack. This is one of the first incidents that show Rick is on a slippery slope. Executed in a somewhat Anvilicious manner as the victim taunted his murderer that he would have done the same thing if given the opportunity.
In a one-off Rogue Trooper strip by Alan Moore, Rogue encountered a Souther scout who was intending to kill a busload of Nort civilians. The scout stole Gunnar to try and do this, but Gunnar responded by shooting the scout.
In Preacher, Jesse's dad iced his racist commanding officer while serving in Vietnam, after the officer's sadism and stupidity got one of Jesse's friends killed.
One issue of The Phantom Stranger involved a would-be revolutionary constructing a metal, robotic "god" (who could shoot and fight like a human) as a symbol of his people - unfortunately, said "god" got interested in the revolutionary's wife and decided to Murder the Hypotenuse this way.
In the final chapters of Uplifted:Revolution, Kampfgruppe Hoch (a thrown together Battalion) learned that no matter what rank you are, you`re subject to summary execution at Joachim Hoch`s own hand should you murder a civilian or a prisoner, even if you`re a Major.
Films — Live-Action
This was how Staff Sergeant Barnes disposed of Sergeant Elias in Platoon. And how Chris disposed of Barnes
The Beast Of War (1988). The Soviet tank commander kills an Afghan member of his crew, convinced he's working for the mujahadeen pursuing them. Also lampshaded between two crewmembers who don't like each other much.
Kaminski: You better watch your ass, Koverchenko. You know, sometimes Afghan snipers pick off tank drivers.
Koverchenko: Sometimes tank drivers pick 'em off first, Kaminski.
Perhaps narrowly averted in The Hurt Locker, where Sergeant James interrupts a bomb detonation because he thinks he left his gloves at the second bomb site. He takes the Humvee with him, leaving Sanborn and Eldritch alone in the sun. Sanborn toys with detonating the second bomb while James is there, speaking ominously with Eldritch about how they would be able to get away with it as well.
Mongol. After the last battle, two men betray their Khan Targutai, the rival and opponent of Temudjin (Genghis Khan), and bring his corpse to Temudjin. Temudjin ignores the body, and orders the two men executed, because they "betrayed their Khan".
Serpico. One of Serpico's fellow officers pleads with him to drop his corruption allegations because his life will be in danger. "They don't even have to shoot you. They just have to not be there when you need them." This is played out when Serpico is caught by a closing door during a drug bust, and his police colleagues don't do anything until after he's shot.
In the late 70s, Carol Burnett starred in the movie Friendly Fire with the main plot being that her son was not killed by Vietnamese soldiers, but was instead killed by US artillery that was being operated by soldiers who were drunk.
Dark Blue World. One of the protagonists accuses a fellow Spitfire pilot of doing this (he'd been sleeping with his girlfriend); when they look at the gun camera footage later it turns out he'd actually been fired on by a German fighter, which was then shot down by by his friend.
In Animal House, Neidermeyer was eventually fragged by his own troops in Vietnam.
In a segment of Twilight Zone: The Movie directed by the same director actually focuses on those selfsame troops, based on an off-handed reference one makes to "fragging Neidermeyer".
In the film Casualties of War, after the rape and murder of a innocent village girl, Eriksson is almost killed by a grenade in the American HQ because he was trying to tell someone what happened.
The movie Assault, made in the 1950s, features a WWII CO whose raw incompetence keeps getting his men killed. At the end, as he climbs a staircase to surrender to the Germans, one of his men finally snaps and shoots him in the back. (This scene made Assault the first war movie to not receive support from the military.)
Most probably happened in Ran, when the general rides up to the second oldest prince to tell him that his older brother was killed by a stray bullet. When the prince looks at the still-smoking musket in the general's hand, he wordlessly throws it away and they never speak of it again.
The finale of Robert Aldrich's Vera Cruz features Burt Lancaster gunning down one of his henchmen for no reason. This finally sends erstwhile partner Gary Cooper over the edge.
In HornetsNest done to SS Major Taussig by his colleague in the Wehrmacht, Captain von Hecht, after Taussig refuses to admit that the vulnerable Della Norte Dam is in danger.
SS Major Kaempffer blows Captain Woermann away in the film version of The Keep.
When two of Major Paul Kreuger's men attempt to desert and run away in The Bridge At Remagen, Kreuger shoots them in the back as they flee.
The preface to the Dragaera book The Paths of the Dead confirms through denial that Adron did this in battle to a challenger to leadership for the House of the Dragon. The two were on the same side, but Adron hired the assassin Mario to kill the other guy during the battle. It's kind of important to learn this, as while Adron comes across as a Well-Intentioned Extremist when trying to seize the throne in the previous book, with the new information, he seems more clearly to be The Evil Prince.
While it's not clear if he actually ordered the assassin in that situation, the conspiracy detailed in the book Yendi also included another of Adron's challengers to the throne being knifed in battle, although in this case at least they were on the opposite side.
The Cadfaelbook / episodeOne Corpse Too Many uses a variation on both this and The Uriah Gambit. After a mass hanging there is an extra corpse hidden among them. The extra corpse was strangled, not hanged — but it turns out that one of those hanged was The Mole and was meant to have been spared, and the villain deliberately set him up to be hanged as well, so as not to have to share the treasure.
The Father Brown mystery "The Sign of the Broken Sword" by G. K. Chesterton. An interesting twist on both tropes: Murderer, General St. Claire, killed his victim first, and then planned an otherwise pointless assault so that it would happen at exactly the same spot, thus hiding his victim among other casualties.
In Sharpe's Waterloo the Prince of Orange (aka 'The Young Frog'), who happens to be Sharpe's immediate superior, is eventually shot by a Rifleman because he's too stupid to lead and is putting everyone's lives at risk.
In the Codex Alera series by Jim Butcher done a couple times. First by Lord Aqutaine with the Crown-loyal soldiers. Then Gaius Sextus does this to Lord Rhodes, in revenge for his part in murdering Septimus.
And Septimus' death is an example of this itself, of course.
This happened at the city of Pale, in Genabackis, in the Malazan Book of the Fallen, during the fight with Anomander Rake and Moon's Spawn; Tayschrenn took advantage of the battle to kill two of the High Mages on his side, and Rake lost the battle because he was investing a lot of his energy just protecting mages on the opposing side from Tayschrenn. Or so it seemed at the time anyway. In truth Tayschrenn's involvement was a lot less of a simple attack on his own side than it appeared at first glance, and less pre-planned. He was in fact more of a good guy taking action against a third party which was interfering, which was misunderstood by the Pov character at the time in the chaos, not helped by those who seemed to believe her and subsequently rebelling against the empire (then appearing a lot more evil than in fact it is — though not being all sunshine and roses of course) being revealed a long way down the line to be involved in a very long term Gambit Roulette with Tayschrenn (although that incident was not a part of the plan) and in fact still loyal.
The AnviliciousStrawman Political 'Operation Chickenhawk' segment of Al Franken's book Rush Limbaugh Is a Big Fat Idiot has a squad of Republicans who avoided service in Vietnam (Limbaugh, Newt Gingrich, Pat Buchanan, and a few others) fragging Lt. Oliver North. A prequel chapter in Lies And The Lying Liars that Tell Them has them do it to every commander until Capt. Max Cleland managed to crawl back to base, whereupon they fled into the jungle. And John Kerry's crew (George W. Bush, Dick Cheney, Bill O'Reilly, and a few others) do it to him and Al Gore, who's on board as a journalist.
In the next novel, Straight Silver, Cuu likewise uses this as cover to murder Sehra Muril. Larkin considers doing this to Cuu, even joining a patrol with his hated enemy to find the opportunity, but agonizes over the shot and ultimately can't take it, much to his later shame and regret.
In Ghostmaker, Sturm ordered his artillery to open fire on the Ghosts because they were chasing enemies and he could claim it was a Friend or Foe situation
In Ben Counter's Galaxy In Flames, Loken tells this to two iterators and concludes it was because he wanted certain men courtmartialed. They conclude that nay-sayers are being eliminated. Later in the book, the Warmaster sends a third of his forces to a planet and virus-bombs them. Only Tarvitz's discovery let any of the betrayed men survive. After the attack, Tarvitz goes to join his Legion's survivors, partly in hope of reorganizing their forces, but part so that he could die with them at need, in defiance of the division the Warmaster had tried to bring.
Attempted by Captain Kila in The Lost Fleet who tried to have the fleet commander Captain Geary killed by some accident or another three times. She only gets discovered when she kills a former ally who managed to leave a message to Geary before her ship blew up.
In the beginning of Homeland, Dinin kills his older brother during the battle with another house. Mind you, no one is fooled. Later, it is mentioned that wizards cannot participate in surface raids - because some guy killed a few drow with a fireball in a raid and claimed it was a malfunction of his magic due to the conditions (the investigators were in no hurry).
This is the final fate of Captain Fisher, a.k.a. "Billy Liar", in Kim Newman's Alternate History novella Teddy Bear's Picnic. His troops frag him by tossing a white phosphorus grenade into his tent while he is sleeping; a practice known as 'white saucing'.
As detailed in "The Spell of War", the first mystery solved by Lord Darcy involved a case of this when he was an 18-year-old lieutenant in the autumn of the War of '39.
The scoundrel Harry Flashman has many opportunities to do this over his scandalous career, but usually chickens out. A notable example is in Flashman and the Angel of the Lord, where he is blackmailed (by Northern Abolitionists and Southern Secessionists) into infiltrating John Brown's gang and assassinating him if his raid on Harper's Ferry looks like it might succeed. During the raid Flashman instead shoots his co-conspirator before he can kill Brown, saving Brown and still fulfilling the trope.
In Memory, Sorrow, and Thorn, this is how Duke Benigaris inherits the throne of Nabban, by stabbing his father in the back during the siege of Naglimund and claiming that it was due to enemy action. This later comes back to bite Benigaris when the testimony of a soldier who witnessed the event is used to incite rebellion against him.
Easy Company were all but cutting cards for who got to inflict this trope on Captain Sobel. Ultimately averted after it became clear that not only was Sobel a martinet and a bully, he had No Sense of Direction and was completely out of his depth in a combat posting, at which point he was posted back to a training role. Some veterans interviewed for the book, presumably with the benefit of hindsight, even opined that his Drill Sergeant Nasty routine made them even more determined to pass Jump School just to annoy him.
In a Star Wars Expanded Universe story, the "Look sir, droids!" stormtrooper does this. He had been a promising AT-AT pilot who was relegated to backwater stormtrooper duty after exposing a flaw in the AT-AT design to its creator. He is repeatedly confronted with the cruelty of the Empire, including the Lars murders and the massacre of the Jawas, and especially of his commanding officer. When he sees his captain draw a bead on Han Solo during the hangar bay fight, he calmly shoots him in the back.
After a border fight, he kills the Clan deputy, Redtail, hopińg he'll be made deputy himself. He places the blame for Redtail's death on Oakheart, whom Redtail had been fighting against and who had been killed in the battle so he wouldn't be around to deny it. Too bad Ravenpaw had been hiding in the bushes and saw it happen...
Wanting to kill his leader in order to become leader himself, Tigerclaw convinces a group of rogues to attack the camp. During the battle, he attacks Bluestar, hoping to make it look like a rogue had killed her.
Near the climax of Prince Caspian, the Telmarine king Miraz duels Peter one-on-one. Peter knocks him unconscious and a full-scale battle ensues. In the confusion, a Telmarine Mauve Shirt Miraz insulted earlier delivers a Coup de Grâce.
A Song of Ice and Fire: During the Battle of the Blackwater, a mysterious employer hires, Mandon Moore one of the kingsguard to deal with Tyrion. Were it not for Podrick Payne, Tyrion almost certainly would've been doomed. As it is, he now sports a truly hideous scar from the encounter, having only barely recognized the threat in time for the first blow.
In The Short-Timers, a Vietnam War era novel by Gustav Hasford, fragging of the Marines platoon leader is implied though not confirmed. It doesn't help that the character in question is both a sociopath and in habit of bragging about his alleged exploits in the area of killing his superiors.
Animal Mother spits a lot because he thinks it makes him look tough. "Lifers never get wasted. Just the ones I frag, that's all." [...] "The platoon radioman was down. Some redneck from Alabama. I forget his name. Took a sniper round through the knee. The Skipper went out to get him. A frag got him. A frag got them both. At least..." Cowboy turns to look at Animal Mother. "At least, that's how Mother tells it, and he was walking point."
Corporal Himmelstoss from All Quiet on the Western Front by Erich Maria Remarque becomes more cautious towards the protagonists after he's transfered to the front, partly because "surely someone fed him with this nonsense about shooting to the back".
In The Stand, after Sergeant Peters executes DJ Ray Flowers, his own men, fed up with they see as senseless murdering of civilians, open up on him on the spot. One shocked private refers to it as "We just scragged Sergeant Peters!"
In The Good Soldier Švejk set during the World War One, sapper Vodička, an old comrade of the protagonist, is quite fond of recounting stories involving unfriendly fire in the Austro-Hungarian military.
"On the Przemyśl front we had Hauptmann Jetzbacher who was a swine, the like of which you won't find under the sun. He bullied us so much that one chap of our company, Bitterlich, a German but a very good fellow, shot himself. So we decided that when it began to whistle from a Russian side, it would be all up with our Hauptmann Jetzbacher. And as soon as the Russians started to fire at us, we peppered him with five shots in a cross-fire. The beast was still alive, like a cat, so we had to finish him with further two, to prevent any troubles. He just growled in a comic way, rather funny." Vodička laughed: "Such things happen daily on the front."
That evening we dug foxholes and cooked C rations over heat tabs. The night was hot, so instead of sleeping right away, I sat with a black friend and helped him pull his watch. He told me that one of the black guys had taken care of the first sergeant. It was an M-79 round, of a grenade launcher. Although the shot was meant only to scare the top sergeant, the blacks weren’t crying, he said.
In the TV series Over There, The Neidermeyer is killed by friendly fire after sacrificing several soldiers to protect a money truck and threatening to arrest another who protested his orders. While the incident is officially labeled as accidental, it is implied that one of the soldiers in the squad shot him intentionally.
In Ultimate Force, Henno clears a room with his commanding officer, picks up an enemy AK-47, and shoots half a clip into his back in retaliation for sleeping with the wife of one of his men. Afterwards he has a Coke.
Battlestar Galactica. After demanding at gunpoint that his troops carry out an ill-conceived attack on Kobol, Crashdown gets shot in the back by Dr. Baltar, who later claims he died "in the best traditions of the service". None of the others dispute this version of events.
Cally uses it to blackmail Baltar in the very next episode, however.
In the first episode of The Shield Vic does this to Terry Crowley
In an episode of the German police series Polizeiruf 110, Hauptkommissarin Johanna Herz investigates a murder during a re-enactment of the battle of Großbeeren (near Berlin), while her husband, a historian, investigates a local legend that Napoleon had a young French officer killed by arranging for him to be shot in the back during the 1813 battle because he had cuckolded him with his mistress, Maria Walewska.
"You ever heard of 'friendly fire'? Well, sometimes it ain't so friendly."
Discussed by Leckie in The Pacific after his Jerkass CO steals a box Leckie looted from a Japanese camp on New Gloucester.
Also discussed at various points in its predecessor, Band of Brothers. Sobel is the most popular subject.
This gets mentioned in an episode of M*A*S*H when a wounded enlisted man dies on the table. When Hawkeye informs his squadmates one caustically questions whether it was an enemy soldier that killed him, or one of theirs. It turns out the soldier was a known thief and con-artist who had been targeting his own squad.
In the Red vs. Blue miniseries "Recovery One", Agent South shoots Agent Wash to provide armor equipment as bait for the Meta and escape from the scene. In fact, she frequently puts her allies in a position to die. Her brother, for example, suffered such a fate, and she nearly gave Delta to the Meta to get away.
In Freeman's Mind, a marine attempts to kill Freeman with a grenade launcher... only to hit his two teammates instead. Freeman theorizes that this is the reason for it.
Freeman: He wasn't even aiming for me! I was just the excuse.
The famous socialist anthem "The Internationale" calls on soldiers to pull this on their officers, rather than shoot their "comrades" on the other side:
No more deluded by reaction,
On tyrants only we'll make war!
The soldiers too will take strike action;
They'll break ranks and fight no more!
And if those cannibals keep trying
To sacrifice us to their pride,
They soon will hear the bullets flying:
We'll shoot the generals on our own side!
In Deadlands, Captain Jasper Stone threatened to shoot his own men for refusing his suicidal orders. They shot him first... then the Reckoning happened, and he promptly rose from the grave and became Death's right-hand man.
Paranoia encourages PCs to take advantage of this: "You're not looking for an excuse to shoot your buddy, you're looking for an opportunity to shoot him while he's distracted."
Skaven life (who are rat-men) is cheap in Warhammer Fantasy. The Skaven are the only Warhammer troops which can shoot into melee and deliberately kill their own. Casualties are divided evenly amongst the Skaven and the enemy. This is known as Corateral Damage.
The special "misfire" charts of many skaven war machines (which the skaven player must roll on when things go horribly wrong with their shot) include a result where the enemy player can choose a nearby skaven unit to resolve the shot against, since someone on the skaven side is clearly trying to settle an old score (or has paid the war machine crew to do it for them).
Orcs have the "animosity" rule that can lead them to (on a really bad roll) attack the nearest orc unit because of some perceived insult. Having a Black Orc around prevents this from happening.
Warhammer 40,000: As mentioned under the Literature examples above, this is something that has a tendency to happen to Commissars, and is probably why all of the novel viewpoint characters are particularly trigger-unhappy when it comes to their own men. In fact, this was an actual rule for Imperial Guard armies in earlier editions when playing the Catachans, since they were based on Vietnam War American Troops, and this is where the practice became most common (in the public's eye, at least). You had to roll for every commissar in your army, with a one in six chance that he was fragged before the battle started.
Also, a possible secret objective in games, particularly Apocalypse* Large scale games where huge and dead-killy units, formations, and assets that are normally unavailable can be used. battles, is to get an allied, but rival character or unit killed. Actually inverted in one White Dwarf battle report, though, where one player's objective was to make sure his commander died gloriously, while another one was tasked with keeping him alive!
Discussed in Schlock Mercenary, just after a wargame in which ex-General Karl Tagon called down an artillery strike on his own squad of hand-painted duck-lobber gnomes in order to ensure victory.
Karl Tagon: If you hate somebody, using them to bait a trap might as well be murder. If there has to be a sacrifice, and it can't be you, it had better be somebody you like. Time-Clone Kevyn: Do you have many friends, General? Karl: Living? No, not really.
In X-COM: UFO Defense, if a trooper gets mind controlled by an Ethereal, you have to kill the soldier or else the Ethereal will use him to attack the rest of your team.
This is basically what happens to Zack (and nearly Cloud) in Crisis Core: Final Fantasy VII. Both were loyal soldiers for Shinra, Inc., but after witnessing the Nibelheim Incident, discovering the truth about the Jenova Project, and being experimented on by Hojo, they were deemed to Know Too Much and a (massive) army of Shinra military police were sent to 'eliminate the escaped experiments', with tragic results.
In Iji, Krotera is such an extreme General Ripper, that when he breaks the truce during a Pacifist Run, one of his troops happily takes it as an excuse to nail him with a BFG and blame it on the protagonist. Iosa The Invincible may also suffer the same fate, especially during a Pacifist Run, as a fellow Komato thinks that Iosa's aggressive nature is not a good thing (not to mention that Iosa knows about her illegal weapon smuggling activities on the side).
After Maniac is first introduced, the colonel giving the mission briefing tells Bluehair that he has permission to shoot Maniac if he "gives you any static". It prompts this exchange:
Bluehair: Should I use missiles or ship's guns, sir? Colonel: Guns. Save your missiles for more important targets.
Blair threatens Maniac with this in Wing Commander III, after the latter makes one of his usual snide remarks when Blair is still dealing with his girlfriend Angel having been disemboweled.
Call of Duty: Modern Warfare 2 has a huge twist towards the end, in which General Shepherd uses Roach and Ghost to obtain information implicating him as the mastermind behind the massive war breaking out between America and Russia, then suddenly executes both of them. He presumably covers it up by claiming they were killed in battle. Note that this is not an inversion since the trope criteria doesn't specify the direction ranks between the victim and perpetrator go, but a superior officer killing his own men in a way that fits this trope is fairly rare.
Shepard tries to do this to everyone in the 141 after Russia declares war, becoming more blatant about it as the game goes on. After retrieving Rojas in Brazil, Shepard blocks the escape chopper, forcing the 141 to call Nikolai to evac them, and letting a few dozen of Rojas's men try to kill them in the meantime. While storming the Gulag, Shepard tries to bring down the castle with the Navy's missiles with the 141 still inside, halfheartedly apologizing by saying that "The Navy's not in a talking mood right now" when the walls start crumbling. In the airplane graveyard, Price and Soap get caught in the middle between Makarov's and Shepard's men, and in Shepard's Afghanistan base, Shepard activates the base's self-destruct mechanism and calls down artillery fire on his own troops to get Price and Soap, saying "For those of you still inside, your service will be noted."
A similar thing happens earlier: Makarov shoots Joesph Allen after the massacring the Russian airport at the end of the mission No Russian, but that's because he knows Allen's The Mole. No, actually, it was part of the entire plan, making Allen a tragic Unwitting Pawn.
Recursive example in the original Call of Duty, at the beginning of the Russian campaign, you (as an unarmed conscript) are directed by a sniper to move to a position where you and he can take out a German machine-gun team. Problem: the new position is slightly further off the line of battle, and Comrade Stalin's orders of "not one step back" are being enforced by The Political Officer, who is gunning down anyone who's moving backward even in a flanking maneuver. Solution: you go first, drawing the political officer's attention and aim, and the sniper clears the way for you.
If you shoot an ally (even accidentally) in Soldier of Fortune II, the others will immediately execute you.
In the Rainbow Six series starting with 3 at least, teammates shout "Murphy! Murphy!" when fired upon by friendly fire or if a grenade accidentally gets thrown near them.
Any collateral damage in F/A-18 Hornet results in court-martialling of the player character.
This method is one way of settling the difficulty with Urdnot Wrex during the Virmire mission in Mass Effect 1
At the beginning of the Fallout: New Vegas DLC Honest Hearts, as you are fighting off the tribals that wiped out your caravan party, Follows-Chalk suddenly jumps into the fray. Unwary players with sniper rifles may accidentally shoot him, causing failure of the main quest.
In Mission 09 of Ace Combat 5, an allied comms during a massive beachhead operation Yuktobanian soil has one soldier request you bomb his own platoon's commander. If you say no, he said sorry to bother you, and immediately informs his friend to "look for another alternative". If you do say yes, he will attempt to give you the coordinates, before seemingly getting Killed Mid-Sentence.
The first mission of Deus Ex has Denton trying to capture a barrel of Ambrosia and an NSF leader. After doing so, a soldier comes up to secure both. Denton can kill him, and that leads to this exchange:
Manderley: "Do you know what happened to the solider we sent in to retrieve the Ambrosia?"
Denton: "No sir. Friendly fire?"
Manderley: "Not so friendly, I'm afraid. I have opened an investigation. Dismissed."
In Star Wars: The Clone Wars, the Umbaran troops, after employing guerrilla tactics for a few episodes, steal several Clone Trooper uniforms, leading to some cases of this. Except everyone killed in that battle was a Clone Trooper, and the Umbarans stealing uniforms was just a ruse by their Smug Snake General, to make them lose the battle, and help him prove himself to the Sith.
Julian the Apostate was the only Roman emperor after Constantine to attempt to revive the pagan religions. He was killed in battle against the Persians, and some have alleged that it was one of his Christian soldiers who killed him.
Similarly, King Charles XII of Sweden dropped dead from a gunshot to the head while peering out of a trench during a battle in 1718. Rumour has always had it that one of his own officers was sick and tired of twenty years of uninterrupted war and blew the King's brains out (using a uniform button for a bullet).
There were also rumours about the death of King Gustavus Adolphus of Sweden in the battle of Lützen (1632) being the work of a treacherous officer of his own army.
Most infamously prevalent during the Vietnam War, where a specific set of informal rules developed surrounding it. For instance, incompetent and cruel officers could be fragged without warning, whilst it was considered fair to warn brave or overzealous officers by way of placing a grenade pin in their bed beforehand, giving them a chance to change their behavior. Some units even offered bounties for the deaths of particular officers. At least six hundred officers are confirmed to have been killed by their own men, while the deaths of another fourteen hundred are considered suspicious.
Also something of a problem during the Wars of the Roses, largely due to the trust issues that were a feature of that conflict. The most spectacular example occurred during the Battle of Tewkesbury in 1471, when the Duke of Somerset confronted his own infantry commander, Lord Wenlock, and demanded to know why Wenlock hadn't committed his men. Before the latter could answer, Somerset dashed his subordinate's brains out with a battleaxe.
During the Mexican War, some unhappy soldiers tried to blow up then-Lieutenant Braxton Bragg with an explosive shell under his bed.