A combat move in which a heroic melee fighter, taking aim at an opponent in front of him, swings a large melee weapon over his head and—accidentally or maybe intentionally—hits an enemy standing behind him, taking him out. Usually this is followed by landing a hit on the enemy in front immediately afterwards (what the fighter wanted to do in the first place).
This comes in handy when the hero is outnumbered in a fight and the adversaries do not practice Mook Chivalry, or when a sneaky attacker is about to stab the hero In the Back while he is distracted by the enemy in front of him.
The Dangerous Backswing is not always lethal. Especially there is the comedy variant in which an overzealous fighter does not realize that his mighty swings pose a threat to his own allies standing behind him, and the very companions he means to protect only narrowly dodge possibly lethal hits or else collect some bumps to the head.
Overlaps with Badass Back. Compare Spin Attack, an alternative way to deal with such a situation. If the backswing hits an ally, it's a case of Friendly Fire. Collateral Damage is basically the missile weapon equivalent. Compare and contrast Offhand Backhand, where the character is perfectly aware of the person behind them and clobbers them without looking regardless of whether they are currently facing a threat frontal. Compare Rod And Reel Repurposed.
- In 101 Dalmatians, Horace accidentally bonks Jasper in the head with a club.
- The Sword in the Stone: As Sir Ector raises his sword over his head to attack the enchanted dishes animated by Merlin's magic, he strikes his son Kay in the head with the backswing. Fortunately for Kay, the blade simply bonks him instead of cutting him. (This scene is Recycled Animation from the scene in One Hundred and One Dalmatians in which Horace bonks Jasper in the head with a club.)
- In Condorman our erstwhile hero, when confronted by a bunch of thugs, grabs his briefcase and swings it back so he can launch it forward at the thug in front in him, only to clobber a thug sneaking up behind him in the face.
- Raiders of the Lost Ark: During the street fight in Cairo, one of the Mooks accidentally hits his comrade when he winds up to hit Indy with a piece of wood.
- In Kung Fu Hustle, Sing and Bone try to throw knives at the landlady, but keep hurting Sing by accident. Bone tries to throw by swinging his arm back and hurling, but stabs Sing instead. Then when they're noticed, Bone lifts a box to throw, not realizing that it's full of snakes and he just dropped a bunch of angry snakes all over Sing.
- The Saga of the People of Vatnsdal: Ingolf Thorsteinsson, who carries the sword Aettartangi, with one supporter picks a fight with a gang of eighteen outlaws. The outlaws attack from all sides, but Ingolf swings Aettartangi so that "the sword fell on the head of the man standing behind him so that he met his death, and it delivered a death blow to the man standing in front and thus Ingolf killed them both with a single blow."
- The Dana Girls book "The Mystery of the Locked Room" starts with one of the girls accidentally hitting a man on the head with a tennis racket, as she was about to demonstrate a strike to her sister.
- In the song "Never Split the Party" by Emerald Rose (a satirical recounting of a Dungeons & Dragons dungeon crawl), the player characters have to dodge the cleric's backswing, implying that they're trying to avoid damage from Friendly Fire.
The cleric swung his holy club, some orcish skulls to break
We tried to dodge his backswing as we pondered our mistake
- In Cricket, a reckless/careless batsman can get himself out by accidentally hitting his own wicket.
- Get Amped: The Skull Bardiche accessory takes the form of a large axe. It is so heavy that, when you do an upward swing move with it, the axe smashes down to the user's back, hitting the enemies on the user's back as well.
- A lot of bosses in Dark Souls swing their (giant) weapons in very wide arcs, so it is quite possible to get killed by them even when approaching them from behind while they attack someone (e.g. a summoned ally) in front of them, simply because the strike either starts or ends well behind their back.
- Chivalry: Medieval Warfare, MORDHAU and other such games that put an emphasis on accurate melee weapon combat have a slightly different version of this as a feature; the backswing of the weapon might not touch you, but the actual swing will begin there and hurt like hell, giving you only a half-second more to react than usual. Exploiting this usually becomes fundamental in the metagame.
- Exploitable in the Castlevania: Chronicles of Sorrow games with the Red Minotaur soul. This soul swings a giant blade back before swinging it forwards in a full 360 degree arc, so it's possible to hit an enemy twice by facing away from them and then swinging.
- In the Tom and Jerry short "The Truce Hurts", Tom, Jerry and Butch the bulldog are having a three-way battle, in the course of which Tom repeatedly whacks Jerry with a frying pan; Butch, who is standing behind Tom vainly trying to hit him with a baseball bat, gets hit on the head by Tom's frying pan with every of Tom's swings, without Tom even noticing. This repeats no less than seven times in a row.
- Disenchantment, episode #5: "Faster, Princess! Kill! Kill!": Trapped in the dark cellar of Hansel's and Gretel's gingerbread house of horrors, Bean is facing Hansel who advances on her with a pitchfork, while Gretel is creeping up behind her back unseen. As Bean swings a double-bladed axe over her head, intending to strike at Hansel, she accidentally kills Gretel by hitting her in the head, then strikes at Hansel, killing him too.
- This is a real risk of using tools like machetes.
- Same goes for fishing rods. A careless cast can strike someone with the sinker or snag them with the hook.