Bifurcated Weapon



""You're holding them all wrong. Keep in mind; these are dual swords. Two halves of a single weapon. Don't think of them as separate, because they're not. They're just two different parts of the same whole.""

- Zuko, Avatar: The Last Airbender

Two weapons are always better than one, but they're awfully heavy to lug around separately. So what's the solution? Rig them to be able to combine as one, that's what! Often used to show that a normally singular-weaponed warrior can actually dual wield, the Bifurcated Weapon is two-two-two weapons in one. Weapons permanently stuck together, like gunblades, are not bifurcated, as they can't break apart through normal means.

The theory behind this is that while you can get more range out of two separate weapons, combining them into one mega-weapon should increase your battle prowess enough to finish off your foe. Most of the time, though, the weapon to be bifurcated is a sword, and it's usually rigged...to split right down the middle, making two mirror images of one sword, making one wonder why it was even joined in the first place. Staves are usually more logical as far as close-combat weaponry is concerned, as the long rod can be broken down into two smaller sticks to handle a more cramped area. And, of course, using this tactic with guns is a no-brainer, but watch out for the increased power/ammo consumption.

A different theory is that these weapons provide the wielder with a strategic advantage by making one's opponent become used to fighting a person wielding one weapon and then suddenly attacking with two, the sudden switch in technique being enough to throw off the enemy's balance, allowing the wielder to obtain victory.

For the most part, these weapons are confined to fiction for a number of Awesome but Impractical reasons. Some examples do exist in the real world, though generally not to the extent seen in fiction. One of the more well-known real-world examples is the bayonetted rifle: Separately, they're a knife and rifle that can be used as such, but by combining them the rifle grants the blade additional reach. A more modern example would be the underbarrel weapons, typically either a grenade launcher or shotgun, which can sometimes be detached from the primary barrel for use as an autonomous weapon.

For another many-weapons-in-one-package deal, see the Swiss Army Weapon, weapons that can change from one form to another, or Mix-and-Match Weapon, weapons made of two different weapons, bearing uses of both. Not to be confused with a sword that bifurcates other things.

Anime and Manga

 * Magical Girl Lyrical Nanoha
 * In Nanoha A's, Signum's sword can be combined with its sheath to become a bow.
 * In Magical Girl Lyrical Nanoha StrikerS, Fate can split the Zamber Form of Bardiche into two normal-sized energy swords and merge them back to its original Humongous Mecha splitting size while in the heat of battle.
 * Also in StrikerS, Teana Lanstar's gun can become two guns or two energy daggers.
 * Touma from Force has a gunsword - like a revolver with a blade taped under it. He could still probably shoot with it.
 * Gundam
 * In the Mobile Suit Gundam, the Gundam's Beam Swords could be combined into a Beam Javelin. This was later dropped in the movies.
 * In Gundam Seed the Buster Gundam normally wields two weapons: a beam rifle and railcannon. These can be combined by docking the barrel of one into the butt of the other, increasing the weapon's output, turning the former into a long-range beam sniper rifle and the latter into an anti-armor shotgun.
 * SEED also likes doing this with melee weapons; Freedom, Justice, and a couple of others can combine their beam sabers into a double-ended saber. The Impulse takes this to the next level by applying the same function to its anti-ship swords.
 * Similarly, the Hyperion Gundam in Gundam SEED X Astray has a beam submachinegun that comes with a Beam bayonet. The bayonet itself can be launched for extra killy goodness.
 * Wing Zero has the twin buster rifle that can be fired as a single unit or split down the middle to be dual-wielded...not to mention the fact that each half of the thing is effectively a mech-portable Wave Motion Gun.
 * Crossbone Gundams X-1 and X-2 possess the Zanbuster, a beam rifle made by combining their pistol (Buster Gun) and cutlass (Beam Zanber) weapons.
 * BB Senshi Sangokuden (and SD Gundam kits in general) feature tons of bifurcated weapons. Some examples:
 * Date Masamune Gundam has a Fuuma Shuriken capable of splitting into a sheathed sword, a flail, a claw, a rifle and two water-walking sandals. They can also combine with his sword.
 * Sonken Gundam's BFS can disassemble into a set of armor and a small folding sword; his upgraded armor turns into a tiger. (And this is without the add-on that can turn into a Musha Dendrobium Orchis.)
 * Choukou Zaku III can detach the blades from his Blade on a Stick and use them independently, or attach them to his shoulderpad and use both pads as boxing gloves.
 * The 00 Qan[T] from Mobile Suit Gundam 00 The Movie have six blade bits that can also attach to its Cool Sword to become double its size. It can also function as a gun.
 * Speaking of the 00 Qan[T], the SD kit version takes this to a ridiculous extent, even for an SD model as mentioned above. By using the the storage device that came with the Exia R2 make to store the parts for the R1, it can attach two long blades, two GN Swords, and the GN Sword V (barely), in order to make a five way...Something. Along with attaching the GN Fangs to the GN Sword V, this makes nine blades in one.
 * Before that, the original 00's GN Sword IIs could be docked end-to-end into a Double Weapon—which Setsuna would occasionally throw.
 * Tengen Toppa Gurren Lagann
 * The title Gurren's shades can be used as a weapon (seeing that they were originally the Gurren's swords before it was captured by Kamina who had them welded together). Occasionally they split into two to pin down enemies, but in the movie they divide into sixteen different shades to pin down a particularly large foe.
 * In episode 22, instead of dividing the shades, Simon uses both the shades and Gurren-Lagann's impromptu jetpack (a fighter that got drilled onto the mecha's back) as boomerangs
 * Rai-Dei the Blade, one of Trigun's Gung-Ho Guns, is a Samurai whose katana sheath can be fired as a rifle.
 * Rurouni Kenshin
 * Late in the show, Yahiko faces an antagonist whose bo split into a six-segment nunchaku, and the ensuing battle demonstrates a fundamental weakness of such a weapon: by attacking it with his succession technique the instant it's about to separate, he puts enough strain on the joints that the entire thing splinters.
 * Another opponent during the Shishio arc was the sword collector, Sawagejou Chou, who used a variety of awesome but impractical weapons against Kenshin. One such weapon was named the Renbatou, featuring two blades parallel to each other (much like Kadaj's sword in Advent Children). The theoretical advantage of the weapon was the severity of the hard to repair wounds created by the blades. Kenshin immediately snaps the weapon with a bit of leverage.
 * Shinomori Aoshi has a scabbard that contains two swords. The second sword is drawn only for Worthy Opponents.
 * In Samurai Deeper Kyo, Tokito of the Taishiro wields one of the four Muramasa blades, the Hokuto Shichisei, which can split into two swords. According to Tokito, this feature stems from the fact that the sword is named after the Hokuto constellation, which is the Japanese name for the Big Dipper. In China and Japan apparently, the constellation is divided into two groups of stars. Likewise, the sword named after it is also divided.
 * The main villain of Lupin III : The Plot of the Fuma Clan begins fighting with Goemon with a staff, but shortly reveals that it can also convert to a set of oversized nunchaku.
 * One of the immortals the protagonist faces in the Highlander anime, The Quest for Vengeance, wields an oversized Chainsaw-Sword.
 * Magmatron of Beast Wars Neo is a Splitting Mecha- although he can split into Landsaur, Seasaur and Skysaur, he is one personality and Magmatron is his default mode.
 * Metal Armor Dragonar's eponymous Humongous Mecha has two beam swords which can be combined to form a Darth Maul-style double-bladed beam sword.
 * In Gun X Sword, Dann of Thursday's BFS has a detachable knife (or maybe a wakizashi) attached to the back of the blade. Sin of Friday and Sen of Saturday are two mecha who can join together and separate freely.
 * Devil Hunter Yohko's Soul Sword had an axe blade built into the crossguard. Once (and only once), she impaled a demon, detached the hilt with axe blade, and used it as a throwing axe to stop an incoming projectile. Being magical, it even reasembled itself afterwards.
 * Mahou Sensei Negima Kaede inverts this with her rather large Shuriken. Word of God says it breaks down into knives to be carried around, however this detail has never shown up. She's never used them separately.
 * One of the bad guys in Genzo wields a huge Iron Club called kanabo. His club, however, has a chained weight hidden in the handle, and he could shot said chains at his enemies in order to disarm them.
 * Senki Zesshou Symphogear can transform her crossbow into Gatling Good. It's exactly how you think it is.
 * in Bleach, Ikkaku combines his sword and scabbard (which he dual wields normally) for his Shikai. Said spear can also split into a three-section-staff.
 * Hōsei Meitoku from Hero Tales wields Soutenkyuu, a bladed bow that can also be divided and used as twin bladed swords.

Fan Works

 * In Kingdom Hearts: Keyblade Masters, the Blade of Aegis is a Keyblade that is made of three individual weapons, each one holding the power of the elements. Only Gummi is able to wield it.

Films -- Live-Action

 * Skeletor's sword in the 2003 remake of He-Man and the Masters of the Universe can bifurcate like this.
 * Alien: Ellen Ripley duct-taping a pulse rifle, a flamethrower, and a flashlight together.
 * In Kill Bill, the leader of the Crazy 88 has a fighting staff that can be pulled apart to reveal two short swords. Somewhat Truth in Television. You can get canes and staffs that conceal one or even two swords, but they're almost always display items.
 * In Phantasm II, Reggie combines two double-barreled shotguns side-by-side to make a quad-barreled version. It only got fired once in the movie, killing every single bad guy in the room.
 * Nordberg in The Naked Gun 2½ goes combining weapons until he builds a howitzer.
 * The Three Musketeers 1993 has the assault on the ship that was to carry the Cardinal's Treaty to the Duke of Buckingham. Porthos encounters a Ninja, who pulls out his katana, then pulls it apart into two swords, and proceeds to show off his sword shuffling skills before attacking. Porthos, of course, mocks his show and cuts a rope holding a grille in place, sending the Ninja below deck.
 * G.I. Joe: The Rise of Cobra. Stormshadow uses two katanas and at one point joins them together to use a single weapon
 * Tron: Legacy
 * Rinzler wields two Discs, which fit together as one.
 * Some Black Guards have batons that splits in two Laser Blades wielded like bo sticks.
 * The One begins with two very similar scenes of a prisoner being transferred, each in a different universe. The cops' equipment is one of the differences; In the first scene, their rifles have attached shotguns.
 * The Sword and the Sorcerer - our hero Talon has a sword which conceals a poignard inside its handle, should the main blade/s be broken. His opponent, Cromwell, meanwhile carries a quarterstaff which houses a concealed switchblade.

Literature

 * In The Beastmaster, the title hero had a staff-spear that could be separated into a mace and... mini... spear... thingy.
 * Sir Apropos of Nothing's staff can split into two batons, among other tricks.
 * In the first 'Darth Bane novel, Path of Destruction'', Bane's lightsaber instructor suprises him during a duel by pulling this trick with his saberstaff.

Live-Action TV

 * In Xena: Warrior Princess, her chakram could be split into two pieces.
 * Ban/Deka Red's twin guns in Tokusou Sentai Dekaranger could combine into a longer sawed-off rifle with more power. The other rangers similarly had batons and taser-rigged knuckle dusters that can combine into a sort of gun. These carried over into Power Rangers SPD, as well.
 * Mighty Morphin Power Rangers
 * Billy's Power Lance. It was used as a staff-like weapon as often as he split it in half.
 * MMPR also had the Power Blaster, made by combining all five rangers' weapons.
 * The Spark Vectors / Chrono Sabers. Double Weapon and Dual-Wielding.
 * Power Rangers Operation Overdrive has Kamdor, whose two swords combine into a double-bladed naginata. In the same season, the Rangers have a weapon that can encase enemies in cement, or be reversed to fire a spinning drill head (in the style of Cement Driver and Drill Driver, two Humongous Mecha introduced just before this weapon.)
 * Also, there have been many instances of bladed weapons that can be re-formed into guns (sometimes by combining with the blade mode's sheath) during the franchise's long history. A few 80s-era Super Sentai series had team guns that could split into shields and swords.
 * In Space/Megaranger had standard Ranger blasters that could separate into two blasters.
 * Overall Power Rangers loves this trope with most seasons having a larger weapon made out each rangers main weapons, and in special cases, combining bifurcated weapons.
 * Kamen Rider Agito's Burning Form has the Shining Caliber. It normally is wielded as a dual-wielded sword, however, when he transforms into Shining Form, it's wielded as a pair of swords.
 * Parodied in Kamen Rider Den-O when the Owner at one point uses a SPOON that is one of these.
 * Takes the form of a hybrid between an axe and a stake in Buffy the Vampire Slayer, which, oddly enough, is referred to as a scythe.
 * Scrubs: Knife-Wrench! For kids!
 * Battlestar Galactica. Pilots are equipped with standard sidearm with a large-calibre underbarrel attachment for explosive rounds that can make Centurions' heads explode. Presumably it also fires specialist loads like signal flares for downed pilots.
 * This may be based off vierlings like the Space Gun, a combination sawed-off rifle/double-barreled shotgun designed as a compact foraging tool, since different game animals are easier to hunt with shot or bullets.

Tabletop Games

 * Dungeons & Dragons also has several weapons that split or have bits pop out to aid in disarm or sunder attempts.
 * The "Adventurer's Vault" supplement for 4E introduces Paired weapons, which are magical weapons that start off as one weapon but have the ability to split into two identical weapons for Dual-Wielding. A nice little weapon for the Ranger on a budget, or who doesn't want to splurge for two different magical weapons.
 * Warhammer 40,000
 * Combi-weapons, essentially two weapons combined into one, with the user able to fire either separately, or together if it's two of the same gun. The Ork race, in particular, is fond of simply strapping two guns together with tape. Sadly, combi-weapons aren't quite as useful as some of the other examples here—combi-weapon generally is a bog-standard weapon plus one-shot special weapon.
 * The old 40K spinoff Necromunda introduced "Exterminator" - a single-use flamer pack attached to melee or ranged weapon.
 * Warhammer 40,000 Roleplay series have "Exterminator" and "Melee Attachment" upgrades. The latter is some sort of a bayonet for ranged weapons - most often normal blades, but there are mono-edged or chainsaw variants; some weapons have those built in. Also, old good Auxiliary Grenade Launcher. Hammer of the Emperor expansion for Only War adds Chain Attachment (chain knife bayonet), Auxiliary Shotgun (single-shot) and Grapnel Mounting - underslung grappling hook launcher (it seems that the only advantage of this is a way to requisition a grapnel permanently, however).
 * And a combi-weapon with melee attachment would be a trifurcated weapon.
 * The Kroot attack scythe-like blades to their rifles.
 * Amongst Necrons, the Warscythe functions as both a deadly melee weapon and still a gauss flayer, as does the Staff of Light.
 * Shadowrun has a few examples (mostly assault rifles with underslung grenade launchers/shotguns), though the rules allow a creative mechanic to bolt together just about anything.
 * GURPS: Martial Arts has stats for adding a number of different functionalities to melee weapons. Both High-Tech and Ultra-Tech have accessories for guns and beam weapons as well as stats for crazy real life stuff like the Cutlass Pistol.
 * In a clear shout-out to Aliens (as well as a nifty way to make up for the severe lack of variety compared to d20 Modern), d20 Future contains rules for combining various bits of tech and, yes, other weapons into any given weapon. With the right modifications, one could make a fully automatic plasma shotgun with attached acid-grenade launcher that can be fired around corners without looking thanks to targeting software integrated into contact lenses. Also, flashlight! Because seriously, screw you, Doom 3.
 * Star Munchkin has several similarly named weapons (the laser, raser, taser, faser and bananafanafofaser among them) that each are considered two-handed weapons, but can be combined freely to form one weapon, with the sum of each part's bonus, and which still only take up two hands. Some players attempt to acquire the complete set for bragging rights. And the bonuses, of course.
 * And most other players keep the Antimatter trap (that turns the bonuses of one item into an equally large penalty) on hand just for using on the first poor fool to try it.

Toys

 * In Bionicle, The Toa Nuva originally used weapons that had 3 modes: staff, two single blades and a third "Transport" mode, with the exception of Pohatu who instead had a pair of claws that could become a ball for him to kick around.
 * Rahkshi staffs have dagger and Staff modes.
 * Whenua Metru used to have a drill (That didn't look anything like a drill) that split into a pair of shovels.
 * Gresh has his Jungle Shield which can be split into 2 bladed tonfas.
 * And given that they're made out of LEGO, their advanced arnaments are limited only by your brick stock and imagination.
 * He-Man and the Masters of the Universe: In the original 1980s version (or at least in a couple of the comics that accompanied the toys), He-Man and Skeletor owned two halves of a bifurcated sword, which they would occasionally combine to combat a serious mutual threat. (Ordinarily, two people both holding the hilt of a single sword would reduce combat effectiveness, but since both swords were magical, Skeletor was a sorcerer, and He-Man was channeling some serious ancient magic, the combined magnitude of magic involved probably justified the awkwardness.)

Video Games

 * Pit's bow in Kid Icarus: Uprising and Super Smash Bros. Brawl splits into two swords.
 * To make a weapon of pure awesome, Gears of War famously had an assault rifle with a chainsaw bayonet.
 * Boc, from Star Wars: Dark Forces II Jedi Knight, is a Dark Jedi who has a "thick" lightsaber that, in times of great danger, he would pull into two smaller sabers.
 * In Jedi Knight: Jedi Academy, some Jedi (not including you) can split their Darth Maul-style light-lances into two lightsabers. Which makes sense, since Maul's saber was effectively made by welding two lightsaber hilt props together—and when it was cut in half by Obi-Wan, he was still able to use one. This trick gave Darth Bane a nasty shock in Path of Destruction, since the Sith hadn't been teaching anyone to deal with a twin-saber style. The player character can also (if wielding a saber staff) extinguish just one of its blades to use medium stance (or to throw it).
 * Devil May Cry 3
 * Protagonist Dante wields Agni & Rudra, a pair of serrated scimitars (that are actually the heads and attached spines of a pair of demons) that he can combine into a Double Weapon for certain attacks. The swords join together by having the "mouths" at the pommels clamp onto one another. Kinda gross now that I think about it...
 * The player may find themselves on the receiving end of this during the fight with Agni and Rudra if they're not careful. Agni and Rudra have separate health bars. If the player kills one and the other gets away and jumps back on top of the statue upon which they were perched before the fight, . Of course, the fact that you now only have one enemy to focus on tends to counteract this.
 * Mass Effect: In the first game, all shotguns come with a powerful long range energy weapon. You and you're team need to have shotgun training, in order to use it, though. This ability is removed for Mass Effect 2, except for enemies, who all still use it. The Downloadable Content Geth Plasma Shotgun will let you use it again, as a Charged Attack.
 * In Metal Gear Solid 4, Snake can find or buy attachments for his weapons, including shotguns and grenade launchers, both of which have three different types of ammo.
 * Most weapons in the Unreal series have two functions. Sometimes their two projectiles can also be combined to form a third, like the infamous Shock Rifle's combo.
 * Weapons in Painkiller have two main functions, some which can also be combined.
 * Final Fantasy examples:
 * Pictured above is Cloud's sword in Final Fantasy VII Advent Children, the Fusion Sword. It's actually six BFSs joined together. And he can simply unclip any of the component swords in the middle of a battle for an instant secondary weapon. A common Fan name for the weapon is the "Swiss Army Sword" (but that's a different trope).
 * The sword also goes by the name First Tsurugi (translated as "First Sword") in the fandom due to a mistranslation of a developer's words. The film creators never got around to actually naming them except for calling the base sword "First Sword", so the general term used for the whole thing is just "Fusion Swords".
 * Surprisingly enough, there do exist cosplay versions of this sword that manage all six parts.
 * In Dissidia Final Fantasy, Cloud has the fusion swords from Advent Children mentioned above, but only in his alternate costume. Normally he wields the first Tsurugi, but when he goes into EX mode it changes to the fully assembled version. When he uses Omnislash v.5 the Fusion Sword does not split into the separate weapons.
 * In Final Fantasy IX, Zidane had to pick between daggers or two-bladed swords, but in Dissidia Final Fantasy, he switches between the two in different attacks.
 * Garland from Final Fantasy I can split his BFS into two smaller swords, in addition to its other functions, in Dissidia Final Fantasy.
 * In both Final Fantasy XII and Dissidia Final Fantasy, Gabranth uses two swords that connect into one.
 * Sazh's pistols in Final Fantasy XIII will fuse into a single assault rifle at the end of an attack combo, while Fang's twin-bladed spear can be pulled apart into a sansetsukon.
 * In Dynasty Warriors Cao Pi wields two swords joined at the hilt that can be separated during some combos.
 * Dual Blade in the Lufia series is one of these... maybe. Different games have shown it as either one or two blades, suggesting it may be able to separate and recombine.
 * A bit old, but this trailer from Arch Lord has it. Never could figure out if it was ingame too because couldn't get it to work. It's near the end battle, look at one of the pikemen.
 * Hubert Oswell's weapon in Tales of Graces is a double-ended blade that not only splits into two pistols, but can be used as a bow!
 * Near the end of  Tales of Symphonia,
 * One old version of Illidan's Twin Blades of Azzinoth in World of Warcraft was a single weapon detachable into two separate ones. The concept was dropped and the live version, available to players, is simply two huge double-headed curved glaives without any possibility of combination into one.
 * In Strife there is the Sigil, an Artifact of Doom Evil Weapon with some assembly required. Any given piece of the Sigil is a devastating weapon but it grows more powerful as they are combined.
 * In one City of Heroes arc, there's a villain named Trapdoor whose power is to bifurcate himself (he's actually summoning alternate reality versions of himself, it seems). If you don't defeat these Bifurcations, Trapdoor's regeneration level goes through the roof, making defeating him impossible.

Web Comics

 * Thaco in Goblins fights with two swords which, when not in use, can be combined into a walking stick.
 * Kevin from Chaos Theory has a shotgun that can split into two pistols.

Web Original

 * Many of the multiform Swiss Army Weapons in RWBY. For example, Cinder's bow, which separates into two short swords, or Sun's staff, which can become a pair of nunchucks (themselves made of what appear to be sawed-off shotguns).

Western Animation

 * Zuko in Avatar: The Last Airbender wields a pair of Dao that are interlocked as his Weapon of Choice, making them appear as a single weapon while sheathed.
 * Truth in Television: Modern Shuang Dao [double knives] like the ones used by Zuko are commonly used in various Kung Fu styles, and look virtually identical to the ones used by the aforementioned firebender.
 * Cheetor in Beast Machines has a pair of short swords that can combine into a single Precision-Guided Boomerang.
 * Parodied in The Simpsons when Homer joins the gun club. Moe demonstrates how to turn one gun into five guns. He does this attaching four different guns to a shotgun and connecting the triggers together with strings.
 * In the 1981 Filmation series Blackstar, the MacGuffin of the series was the "PowerStar", a sword which was split into two halves, the "Power Sword" and the "Star Sword".
 * Skeletor in the 2002 He-Man and the Masters of the Universe cartoon has a two-bladed sword which can be divided into two when he needs to dual-wield.
 * Robin from Teen Titans once slapped two of his bird-a-rangs together, somehow turning them into a sword. It didn't make sense, but it was cool.
 * Asajj Ventress of Star Wars: The Clone Wars and other series taking place in the same timeframe plays this relatively straight, combining her two lightsabers into a double-bladed one. It's a slight variation though, in that the combined weapon has an S-shaped hilt, due to the curved shape of the individual sabers.
 * Galtar and the Golden Lance: The titular hero wields the titular weapon as a pair of sabers, which can join together at the pommel into a Double Weapon or a more powerful sword, it also retracts into a double pommel-shaped stick.

Real Life

 * The iconic real-life example of the Bifurcated Weapon is the Japanese kusari-gama, a combination of a weighted chain attached to a sickle. Some samurai used this weapon instead of a sword; the chain could be flung high to wrap around a horse-rider and dismount them, pulling them down to the ground where they could be finished off by the sickle's blade. (Keeping both sickle and chain in two hands gives you a lot more strength for pulling someone.) The kusari-gama looks exotic and deadly, so it's very popular in movies, television, and anime.
 * There is a katar, an Indian punching/stabbing weapon, displayed at the City Palace Museum in Jaipur with two single-shot pistols built into either side of it.
 * The more mundane and realistic bayonet attached to a gun counts for this trope too - it's a knife attached to a gun. Traditionally, this turned the gun into a spear; today, the knife is often just used as a knife as well as a spear.
 * Tragically averted by very early versions, which fitted into the barrel and so rendered the gun part totally useless.
 * Plug bayonets were used when formations had closed to one-on-one contact, or when the user ran out of bullets. remember, we're talking Napoleonic and pre-Napoleonic tactics here.
 * A sword bayonet turns the rifle effectively into a halberd - good only not for thrusting attacks, but also for blows and slashes. Before the modern medicine very few of those who had been attacked with a rifle equipped with a sword bayonet were able to survive alive
 * Related innovations placed axe heads on the barrel.
 * Not quite sane, but also implemented: chainsaw bayonet (see the source of inspiration above). Like this. Just don't fall asleep with it.
 * Given the long reloading times of early firearms, they were sometimes combined with a backup weapon. Some examples are the pistol dagger, pistol sword and shield pistol.
 * Some firearms use a sheathed axe as detachable shoulder stock. A discussion on Forgotten Weapons turned up more examples, from Wellington's double barrel flintlock horse pistols to a weapon in Soviet spaceman survival kit (this one was 2x 32 gauge shotgun + 5.45, with machete-stock).
 * Some versions of bo could be released or unscrewed to split into a tri-staff for closer combat or crowd control. Of course the problem is, it can't be reversed quite so easily.
 * The sarissa, a gigantic 20-foot pike used by the Macedonian phalanx under Alexander the Great, was able to split apart for transport. Theoretically the two ten-foot sections could have been used as weapons, one with the spear head and the other using the weighted end that kept the sarissa level. If it ever was used this way, however, history has not recorded it.
 * Well, one historian has interpreted the remains of metal tube-like things as being for joining the two halves together. He was criticised quite a bit for, shall we say, less than rigourous research. It also just so happens that later pikes would incorporate identical metal things on the end, to prevent the enemy cutting the end of the pike off, and weren't able to be split in half. He might have been correct, but it seem rather unlikely.
 * Another example from ol' mundane reality is the current vogue for putting a grenade launcher under the barrel of a rifle. There are also ways to put a stripped-down shotgun under the barrel, like the Knight's Armament Masterkey and the M26 Modular Accessory Shotgun System. And the rocket enema launcher - sorry, "Rifleman's Assault Weapon" system, for payloads larger than what a grenade launchers shoot.
 * Nerf:
 * One type of Nerf Dart Tag blaster pistol (called the Crossfire or Strikefire, depending on which set it's in) was designed with this in mind; while nearly every single Dart Tag or N-Strike blaster has a sight rail for attaching accessories like sights, scopes, lights, and the like, the Crossfire/Strikefire instead has a clip that attaches to those sight rails, allowing it to be combined with other blasters.
 * The Nerf Titan ASV-1 has a similar concept: part of its construction is a reverse tactical rail, allowing any gun with a rail to be attached to the right side. Example: the Maverick REV-6.
 * The more modern Longshot, known as the Nerf Brand Sniper Rifle, is also capable of separating into two guns.