Mahou Sensei Negima! has Magitek bullets able to alter space-time at the point of impact. They were used to send people three hours into the future, but it's implied they can also displace the target to a nearby location. Negi used magic blast guns and strip laser beams.
Outlaw Star had 'Caster Shells' — magic in a bullet. Special mention goes to Number 4 shells, which fire miniature black holes. Their effect on Gene's unfortunate enemies produces some of the more frightening scenes of the series. What they do to Gene when firing them isn't exactly pretty either.
In The Melancholy Of Haruhi Suzumiya, Haruhi subconsciously modified model guns into firing pressurized water balls with unimaginably explosive firepower. Dual squirt guns turned dual mini water-grenade launchers/pistols.
Mista has six little creatures for his Stand. He uses ordinary bullets, but the six creatures (named "1", "2", "3", "5", "6" and "7") can fly and deviate the trajectories of bullets (with kicks), making it possible to Mista to hit targets beyond a corner, to say one. At least one time some of them ride a bullet to reach the target faster, although they never strike him on their own.
Part 4 has Yoshikage Kira combining the power of his Killer Queen stand and Stray Cat's to create invisible shots of air that explode.
Teana from Magical Girl Lyrical Nanoha Striker S has Cross Mirage, a pair of handguns that shoot magic. From the same franchise, there are Cartridges, which are condensed magic in what looks like a firearm shell, but these are not actually shot, just exploded to supercharge a Device.
The Sonic Driver (Sonic Power Cannon in the dub) in Sonic X that fires the title character as its ammo counts here.
An assassin used a unique weapon against her wealthy target: a shotgun, built into her forearm, that fired rolls of coins.
In the episode "Testation", a rampant Spider Tank—which had dodged or neutralized everything else thrown at it—gets stopped by a gun that fires canisters of some kind of quick-hardening glue. Gumming up the tank's legs being the only means of stopping it, short of using weaponry too powerful for use in an urban area.
Togusa used a tracer bullet loaded into his Mateba Autorevolver to tag a fleeing car.
In Fist of the North Star, there is a technique in the Nanto martial arts that involves launching the practitioner out of a cannon while they hold a sword.
One chimera ant in Hunter × Hunter used an airsoft sniper rifle to fire huge fleas (which somehow survived the brutal impact) to make the victims bleed to death due to their bites preventing coagulation.
Macross 7's Nekki Basara pilots a robot that shoots speaker pods (Thoughtfully loaded with glue so the target won't be killed by cockpit depressurization) and sings to his aggressors, hoping to make them give up fighting. He also keeps in reserve a scaled up cannon larger than his own machine for use on battleships.
Mr. 5 loads his revolver with his BREATH. However, his devil fruit power let him make any part of his body explode, breath included. How he was able to tell where his breath bullet was after fired, we'll never know.
Usopp uses pachinko balls for his slingshot Kabuto and whatever he could get his hands on prior to that (Rotten eggs, Tabasco balls, small rocks...). After the Time Skip, he uses Pop Greens, insta-growing plant seeds.
Kai in Blood+ has a gun that fires delayed exploding bullets, with the last bullet of each magazine triggering the others to explode simultaneously. This is used to overcome the Chiropterans' substantial Healing Factor. It can still only slow them down.
Reborn is an adorable baby mafioso who has a gun that, if shot in the head by it, you die. And then come back to life, in your underwear, for five minutes, with the ability to complete your life's ambition. If you complete said ambition, you get to continue living. If not, you perish. Again.
Xanxus and Gokudera also have guns that fire Dying Will Flames (although Gokudera's is more of an Arm Cannon). Xanxus uses his own Flames of Wrath as ammo, while Gokudera loads his gun with dynamite.
Mic Sounders the 13th can fire a GaoFighGar with Goldion Hammer. BEST. AMMO. EVER.
Letter Bee has Letter Bees (postmen with special training to fight enormous monsters) tote around a special kind of gun that shoots a fragment of their 'Heart', something equivalent to their life force in this series. They're important because Letter Bees drag letters around a dark, miserable world where 70% of the land is crawling with giant almost-invincible monsters in order to do their jobs...
The main character Yusuke Urameshi and his Rei/Spirit Gun.
The character Sniper has the ability to imbed his spirit energy into any object and fire it with the velocity of a bullet, generally making said objects much stronger in the process. Ammunition used includes: pencil erasers, dice, marbles, blades of grass, rocks, an absurd amount of knives, and A GODDAMN TRUCK. Abnormal Ammo, indeed. However, when he's done screwing around he justopts for a gun.
The gun had a particular function: the truck was loaded with fuel (why Yusuke had not destroyed it yet), and the bullet blew it up in Yusuke's face.
Alucard's first gun fires 13mm explosive steel/silver alloy rounds (the silver is also melted from a cross from a cathedral), Victoria's Harkonnen fires 30mm armor-piercing depleted uranium/silver alloy or incendiary shells, and the Jackal fires explosive shells encased in Macedonian silver with mercury tips.
Alucard: It's perfection, Walter.
In the last episode of the anime he manages to pull off firing actual melted silver from a cross with his half wrecked gun. He manages it because he is Alucard.
Canti's gun in FLCL uses... Naota himself as ammo, albeit rolled into a flying, glowing red ball.
Et Cetera is about a girl with a gun that shoots the essence of the animals in the Chinese Zodiac. The gun is powered by rubbing the barrel against any item that is made from the animal represented in the zodiac — including a bikini made from Tiger skin.
In Digimon, the Garbagemon wield bazookas that fire faeces at their targets.
Riruka's gun fires miniaturized objects that enlarge in midair.
A gun wielding quincy fires bullets of reishi that look like the quincy cross and can set fire to people.
Perhaps as compensation for only ever being issued six bullets, Daisuke in Heat Guy J is usually provided with one devastatingly explosive "Red Cap" round.
During the "Tower of Hell" chapter of Eyeshield 21, Hiruma uses bullets that are actually pellets full of desiccant powder, designed to make the ice being carried by the candidates for a spot on the Devil Bats melt faster.
"It's a gun, Frank. A gun that shoots swords." FWOCKA FWOCKA FWOCKA FWOCKA
The Joker has a BANG Flag Gun, for all your Double Subversion needs. Pull the trigger once, it sends out a "BANG!" flag. Pull it again, and it fires the flag (which has a pointed tip) into the victim. He once pulled out a gun that had a "CLICK!" flag in it, so that he could declare, "Damn! Misfire!"
In Judge Dredd, the Judges' standard Lawgiver sidearm has several types of unusual ammunition in addition to standard ammunition which can be easily switched as needed. These types include ricochet, heatseeking, incendiary, armour piercing and high explosive. All of the above are usable in the FPS video game too.
Memorably parodied in a Dredd story set in Ireland, where terrorists use "spud guns" which lethally fire potatoes in various forms - mash, chips, etc - culminating in the memorable line, "Spud guns to roasties!"
The minor DCUBatman villain the Condiment King uses guns that shoot, well, condiments like ketchup and mustard. Pretty silly, until he uses hot sauce based guns and spice powder to blind people and burn their throats.
A later issue of 52 has Will Magnus using bullets that are miniaturized versions of his Metal Men.
Gold Digger had Brianna Diggers experiment with "Peebo bullets" based on her robot pets in one issue. They were supposed to seek out and hit bad guys on their own, thereby making them perfectly safe for bystanders; unfortunately their limited AI gave them a rather broad view of what actually constituted a 'bad guy' and hilarity predictably ensued.
One of the stormtroopers in Twisted Toyfare Theatre once built a gun that shoots lightsabers. It ended up destroying a planet.
Dr. Doom built a Spice Cannon that uses Baby Spice as ammo.
In a grimmer take than most, in the accompanying material of Watchmen there's an excerpt from Tales of the Black Freighter in which the pirate crew uses half-rotted human heads as ammunition for their cannons.
In issue 11 of Planetary, John Stone fires a bullet that appears to have a tiny chainsaw blade on one side, called the "Rip-Round," to rupture the fuel line for cyborg Bride's getaway plane. He could have used a normal bullet.
Spy Boy's gun, the Magnum Opus, fires a variety of these.
Fantomex had sentient homing bullets made from malleable skin. They even had human faces on them.
Fallout Equestria: Project Horizons features Blackjack's super gun "Trottenheimer's Folly" which fires what are called "Silver Bullets" that are made of Moonstone, Asteroids/Sky Iron/Star Bones, and Radioactive Magical Mutation Goo.
In Who Framed Roger Rabbit, Eddie Valiant's toon gun fires bullets... semi-intelligent cartoon bullets that can talk, chase down criminals, and apparently return to their case independently. One even carries a large tomahawk. Unfortunately, almost all of them (save the one with the tomahawk) were too stupid to figure out which way the bad guy went. In the English version, they're known simply as "Dum-Dums". In the Italian dub, they are called "mezze cartucce", an Italian phrase used to say "idiots", but with the literal meaning of "half cartridges".
The same movie also features a gun that bops someone on the head with a hammer from close range, and another that springs out a punching fist.
When a certain character finds herself weaponless, she finds a box of ammo. So what does she do? She grabs a handful of bullets and throws them at the bad guys, taking them all out.
One of the weapons featured in the Mind Screw movie eXistenZ is a bone gun that fires human teeth—using chunks of jawbone as cartridges.
In the kid's gangster movie Bugsy Malone, all the gangs were developing machine guns that threw cream pies.
The battle between the "Black Pearl" and the "Interceptor" in Pirates of the Caribbean occurred after a chase in which the crew of the Interceptor, desperate for more speed, threw almost everything they had overboard ... including most of the cannon shot. They were reduced to loading up, in the words of Will Turner, "anything! Everything! Anything we have left!", including cutlery, into the cannons as makeshift ammunition. This is Truth in Television, to a degree. Scrap metal and chains were often used as anti-personnel cannon loads, and indeed, had they not been fighting undead pirates it might have worked. Using an undead monkey as ammo carries slightly less verisimilitude.
The Incredibles: Syndrome's lair on Nomanisan Island utilizes sentry guns that fire sticky inflating balloon rounds to nonlethally stop any erstwhile superheroic intruders. According to some of the commentaries, that was the only kind of weapon they could think of that would conceivably stop Mr. Incredible without killing him and/or destroying the base (it may have also been lightly based on real nonletheal weapon concepts currently in development).
These have also been interpreted—probably incorrectly—as a Shout Out to another balloon-like weapon used to keep people captive on an island: the Rover from The Prisoner.
In G.I. Joe: Retaliation - its trailer, no less - we are treated to a motorcycle that is made of ROCKETS. Which are immediately fired into a building after said bike is ramped into the air and its rider leaps to safety.
xXx gives Vin Diesel a modified revolver that shoots interchangeable rounds, ranging from knockout capsules complete with fake blood to some kind of surveillance bug. This actually backfires on him late in the film; because he's got the gun loaded with non-standard rounds, he ends up pointlessly firing a radio transmitter bullet when he's trying to retaliate against the mooks armed with good old-fashioned machine guns. He then switches to an explosive bullet for a better distraction.
In Young Guns II, Billy The Kid kills a sheriff with a shotgun filled with eighteen dimes (nine in each barrel) used as slugs. "Best dollar-eighty I ever spent!"
This particular event is inspired by something the real Billy the Kid did once when cornered without normal ammo.
Similarly to the above, in The Crow Eric Draven blows up Gideon's pawnshop by spilling gasoline all through it and firing a blast from a shotgun he'd stuffed with dozens of pawned/stolen rings (although it did have a normal charge in it as well).
District 9: The "pig cannon." According to the director, there actually are random pig carcasses lying around South African slums, so the Powered Armor using one as ammo for its gravity gun isn't so weird. Actually... it is pretty weird, but Rule of Cool applies.
On Gru's side, the Fart Gun, although that one was by mistake since he really wanted a dart gun.
Dr. Nefario: I was wondering, under what circumstances would we use this...
The second film gives us the "jelly guns" which, as the name implies, fire foul-tastingjamthat contains an antidote to the PX-41 serum, returning all Gru's minions back to normal when hit. The fart gun also makes an appearance as well.
In The Return of the King, in the battle for Minas Tirith the trebuchets in Minas Tirith hurl broken-off chunks of the city's buildings, a metre or more across, at the attacking Orcs.
Blade explored this in all 3 installments of the franchise. "Daylight flare" bullets that expose vampires to a momentary deadly flash are especially prominent.
Somehow even vampires and werewolves can fight with guns in Underworld - as the vampires use silver bullets (later filled with liquid silver nitrate due to the werewolves pulling them out too quickly), while the werewolves load their guns with bullets that contain an irradiated fluid—irradiated with ultraviolet light.
The Smurfs make use of golf balls, bowling balls, needle-laden fruit, and lipstick when forced to fight Gargamel near the end of The Smurfs.
In Tomorrow Never Dies, the villain has buzzsaw torpedoes which can not only cut through the hulls of other ships, but can be guided through said ships and travel upward if necessary.
In Conan the Barbarian (1982), Thulsa Doom uses a snake as an arrow. Apparently he heard of a "bow and arrow" and thought it meant "bow and adder", or perhaps boa and arrow.
One of the most famous examples of this trope in an otherwise forgettable movie, Most Wanted introduced the concept of a bullet made of ice, the idea being that the round would melt in the target and be completely untraceable. It led to a slew of people asking if such a thing was even possible, until the Mythbusters proved otherwise. This even gets lampshaded by the protagonist. "Ice bullets? What's next, Tooty-Fruity flavor?"
In "Hellboy" the titular character's revolver shoots at least two oddball rounds: one drips a glowing fluid from the wound to make a monster easier to follow, the other is a clear canister containing holy water and bits of silver, wolfsbane, white oak, garlic, and other substances hated by supernatural beings.
An early 1980's film "Runaway" featured a gun which fired small heat-seeking missiles at a speed slightly slower than an athletic man can run. Presumably its designer believed in giving targets a sporting chance.
One of the weapons that Max uses is a modified AKM that uses airbursting explosive ammunition, each round as powerful as modern-day 40mm grenades. This literally makes this weapon into an full automatic fire capable grenade launcher.
There's also the remote-triggered explosive shotgun slug, which packed enough explosive power to disable a ship engine. And then we have Kruger's explosive shuriken.
In The Thackery T. Lambshead Cabinet of Curiosities, the Bear Gun is mentioned at the very end. It shoots bears. Read that again. Tiny bears are used as the ammunition, which expand at some point after leaving the barrel.
In Logans Run, the Sandman cops carry The Gun, which is a 6-shot revolver where each round is different. Among its payloads are a regular bullet, an expanding net, and a heat-seeking bullet. Oddly enough, they don't seem to carry backup rounds...
The Prince Roger series has "bead rifles", which use mass driver technology to propel glass beads at hypersonic speeds. The energy release at impact is very destructive. Glass beads are cheap, easy to make, extremely hard, and tend to shatter on impact so you don't need to worry about over-penetration. A mass driver will presumably let you fire them without breaking. Even more exotic is tightly coiled net made of monomolecular filaments that expand upon firing. They make mincemeat out of unarmored targets.
In Un Lun Dun, Deeba acquires the UnGun, which fires larger amounts of whatever you put in it. It, among other things, fires hair and ants. This is WAY more badass than it sounds and then it fires nothing...uh, well, more like "unfires," acting like a vacuum to suck up the Smog.
The Bas-LagCycle has a race of cactus-people (known as the cactacae). While they can be punctured by bullets, crossbow bolts, arrows and the like, their complete lack of internal organs makes such weapons next-to-useless. They're also enormous, extremely strong, and covered with spines, which makes close-range weapons like blades or clubs viable, but an extremely risky and inadvisable option for most people. A sort of crossbow called a rivebow was invented to get around this problem. It fires huge whirling chakris that can sever the heads and limbs of humans and cactacae alike, but the rivebow itself is so heavy and unwieldy that usually only other cactacae carry them.
The evil Delta Force soldiers of Dan Brown's Deception Point carry guns that can make ammo from nearly anything you jam in the barrel, from ice to sand.
The Martians in Ray Bradbury's The Martian Chronicles use a gun that shoots live bees, the idea being that the moral responsibility for the actual killing is laid on the head of the living projectile, and the gun-wielder's role is mitigated to that of an accomplice. Proves every bit as effective as earthly firearms. Bizarrely enough, this is a subtrope in its own right.
Jack Vance's The Demon Princes series puts in the hands of its protagonist a device that fires "slivers of explosive glass" and either another device or the same device with different loadings/settings, which discharges very fine needles that cause intense and prolonged itching.
In the Discworld books, Detritus the Troll uses a converted siege crossbow loaded with a bundle of regular crossbow bolts. The firing speed is high enough that the ammo generally shatters and then bursts into flame (or vice-versa) ending up in a supersonic flaming ball of wooden shards, which is why it's called 'the Piecemaker'.
John Dickson Carr's novel The Plague Court Murders involved a murder where the victim was shot by a bullet carved from rock salt that dissolved in his body, leaving no trace.
In Larry Niven's Known Space universe, agents of ARM generally use guns that shoot crystallized doses of fast acting sedative. How or why this is better than tranquilizer dart guns is unknown. Probably it's better because the ammo is smaller and lighter. A dart gun has to shoot not only the tranquilizer, but also the syringe that delivers it; a "mercy pistol" only has to shoot the tranquilizer itself.
At least one Poul Anderson short story involved tranquilizer darts that, if they hit a wall or armor instead of flesh, would break open — and then the drug inside would instantly volatize into tranquilizer gas.
In The Holmes-Dracula File, the Count made a point of congratulating Holmes for thinking to use wooden bullets. This one is a fairly common strain of Abnormal Ammo. It's the secret weapon used to tip the balance of power between warring vampire factions in the film Sundown: The Vampire In Retreat, while the vampire-hunter squad in the excellent TV series Ultraviolet use a high-tech, hardened-carbon variant.
In another Saberhagen vampire book a contemporary police officer improvises a wooden projectile by sticking an ordinary wooden pencil into the barrel of his revolver.
In the Star Wars Expanded Universe novels, every ranged Yuuzhan Vong weapon fits this description, from the living ship that fired miniature black-holes to the sword/spear/staff/whip/snake that spat venom.
The J.T. Edson short story "Some Knowledge of the Knife" was a murder mystery in which the assassination weapon was an oddly-balanced knife fired from a large-bore "wall gun".
In James Kennedy's The Order of Odd Fish the Apology Gun shoots... well, apologies. However, they can range from extremely sincere to lethally sarcastic.
In Krabat, golden bullets are the only ones that can kill magic users. At one point, a golden button is used as a bullet.
In Sharpe's Revenge, our hero is severely outnumbered (as usual) but does have a chest of gold coins, which he fires at the approaching enemy. This is not to kill them, but to get them scattering to pick the coins up so he can escape.
In R. Austin Freeman's story "The Aluminium Dagger", the specially-made titular weapon was shot out of a Chassepot rifle to create one of the most far-fetched locked-room murder mysteries yet.
In the Dark Future setting, explosive rounds are remarkably widespread in everything from pistols up. GenTech manufacture a special version of napalm that genetically bonds to skin on contact and continues to burn underwater and inside of people. They also make smart bullets, referred to in-universe as 'smugslugs,' that can track human heartbeats.
In what may be the most lethal example of all, the Speaking Gun from the Nightside series fires words... specifically, the Words of God, inverted. Whatever God created, the Gun can unmake by speaking the Word of Creation that brought it into being, backwards.
In The Chronicles of Amber, the only substance that can be used as a propellant for firearms in Amber is jeweller's rouge.
In the Star Carrier series H'rulka ships carry guns that fire what amounts to a miniature black hole at their targets. The weapon can easily one-shot smaller Confederation vessels at longer range than most of them can return fire from.
1066 and All That explains that one advantage of the Roundheads having perfectly round heads was that, "if any man lost his head in action, it could be used as a cannon-ball by the artillery (which was done at the Siege of Worcester)."
Spudgun in Bottom was named for his ability to fire potatoes out of a certain part of his anatomy.
Richie: Why do they call you Spudgun?
Spudgun: Give me a potato and I'll show you why.
Eddie: No-no, you don't want to see that Rich!
Richie: And why do they call you Hedgehog?
Dave Hedgehog: Give me a hedgehog and I'll show you why!
The wormhole weapons in Farscape can shoot a) black holes that grow geometrically or b) wormholes that can then shoot chunks of plasma-hot star at a target. If you include the Peacekeeper Wars TV movie, you get to see both occur in the course of the series. While it isn't immediately obvious, what the wormhole weapon did was connect two points in space - a sun and an enemy ship. That's where the plasma came from and that's why it's so cumbersome to use.
Parodied in X-Play in which auxiliary character "Johnny Extreme" proposes a video game idea that involves Rocket Launchers that shoot chainsaws that explode.
They have made air cannons that have shot the following: conventional cannonballs, baseballs, chickens (frozen and thawed), straws and twigs, piano wire, Kevlar-wrapped steak, a net, styrofoam cups full of liquid, and a whole host of other strange items. There was also the section of sewer-type pipe they modified to shoot Buster, their much-abused crash test dummy, with a blast of high explosives. The ice, gelatin, and frozen meat bullets mentioned elsewhere in this trope were all tested and all were busted. They also modified a rifle to fire a penny—this time, it was potentially lethal.
Also, inspired by the Pirates of the Caribbean example, they loaded up a whole variety of odd ammo into a US Civil War era cannon to test their effectiveness. Examples included bottles of rum, wooden legs, silverware, steak knives, nails, lengths of chain, and cheese, with varying levels of effectiveness.
Cigarette butts shoved into the barrel of a shotgun, which proved to be potentially lethal at close range. (Unsmoked cigarettes were less useful, and almost resulted in a false Busted.) Additionally, those were supermarket cigarettes; the myth in question involved a couple of hillbillies, so they probably smoked roll-your-owns—no lightweight filter, more mass, more impact force...you get the point.
Or the Korean Hwacha. A salvo of arrows. Arrows propelled 500 yards by gunpowder rockets. That then exploded when they land.
Or the bowling ball fired from a modified gas cylinder, using match heads as propellant.
Soda. It started with styro cup with ice, cup with soda, soda and ice, slushy, and culminated w/Jamie's shoulder-mounted pop-gun.
Not strictly ammo, but in a late 2009 episode, they built a cannon out of duct tape. That fired a five-pound iron ball several hundred feet. They've also built and tested both a wood cannon and a leather cannon.
Finally, they created a hook cannon for a Batmobile high-speed turn myth.
The Royal Canadian Air Farce segment "Chicken Cannon: Target of the Week". Originally a dig at pitiful mid-nineties Canadian military budgets, the cannon was used to fire upon pictures of whomever the show's writers thought were deserving of a little public humiliation. The traditional projectile of a rubber chicken was often supplemented with "custom" ammo suited to the situation at hand (e.g., sawdust for someone involved in the softwood lumber dispute, or Eggos for a politician who was perceived to waffle. And sometimes Jell-O for the hell of it—or, more accurately, because there's always room for Jell-O.)
On Supernatural, the Winchester brothers used shotguns loaded with rock salt for ghost-dispersal.
Doctor Who. Shotguns loaded with rock-salt are used in "Image of the Fendahl''.
This happens to be Truth in Television, rock-salt is sometimes loaded into shotguns to cause pain but little damage.
Get Smart. A KAOS assassin posing as a vampire used a gun that fires twin ice bullets, leaving the distinctive Vampire Bites Suck mark, but no evidence of any weapon.
The final episode of J.A.K.Q. Dengekitai featured the heroes launching a rat out of a cannon. More appropriately, it was a missile that turned into a rat in midair.
The A-Team once built a couple of cannons that shot cabbages at the bad guys. Yes, cabbages.
While pursuing a bad guy in Bones, Brennan and Booth were stunned by the bomb the perp dropped. You know how bombs sometimes have nails and such attached to them to increase damage? This one had human teeth.
In the recent episode "The Shot in the Dark", a stalker at the Jeffersonian shot Brennan in the chest. While she was recovering from the gunshot, the Squints were stymied at the lack of either a bullet or an exit wound. Hodgins considered the ice bullet theory, but recognized that ice bullets would vaporize in a conventional gun due to the heat of igniting gunpowder, and since ice is less dense than lead they wouldn't do that much damage anyway. He later suggested the theory that Brennan's would-be killer used a high-powered air-brush as his 'gun', and froze human blood inside a container of liquid nitrogen to produce the bullets; since blood plasma is denser than water, the frozen blood would make an effective bullet, and melt seemingly without a trace. The fact that Brennan at one point suffered complications from receiving the wrong bloodtype, although hospital records confirmed she received the correct type, also pointed to a blood bullet. Brennan was able to prove Hodgins' theory by undergoing exploratory surgery that allowed the doctors to retrieve traces of the blood bullet that nicked her ribs.
Top Gear once used a gun that fired cars. The kind you drive. In the episode, they fired a selection of old cars into a quarry. At a colossal dartboard. Richard Hammond won. By crushing a caravan with a flying Volvo.
The 1982 BBC adaptation of Day of the Triffids included an anti-Triffid gun which fired little spinning sawblades at the Triffid's slender stems. It didn't see much use, perhaps because the writers realized it was "Day of the Triffids", not "Day of the Humans".
In one Far Side strip, a burglar is confronted by a man with a gun that shoots Doberman Pinschers. Called, appropriately enough, the Dobie-O-Matic (the gun, not the ammo).
The catapult in Medieval Madness fires bowling balls, cats, chickens, cows, and a skull.
BattleTech has the Needle pistol, which uses solid blocks of plastic as ammo. It rips off bits of plastic and fires them as a horrifically effective anti-personnel bullet. There's Inferno missiles which are essentially napalm rockets, and artillery that shoots radar jammers.
Guns that fire shells which explode after they're embedded into a target? Standard issue for the Space Marines.
Guns that fire molecular-edged shuriken? Standard issue for the Eldar. Additionally, guns which fire nets made of Razor Floss. Also, guns that fire miniature black holes.
Tyranids use biological guns which use muscle impulses to fire killer beetles, killer maggots, acid crystals, floating spores or exploding tumours.
Orks use the same exploding ammunition as the Space Marines, but they also have guns that fire tiny goblins. Fired into you. Through Hell.
Dark Eldar probably take the cake. Guns that fire screaming wires that make anyone they hit explode, guns that fire poisonous glass shards, guns that fire the captured souls of tortured psychics. It just goes on.
The Necrons use guns that strip off your armour, flesh and organs layer by layer.
Sternguard Veterans carry into battle special issue ammunition for their Bolters, hellfire bolts carrying mutagenic acid,Vengeance Rounds using "unstable flux core technology" to take out power armor users, and everything in between.
Plague Marines have the shrunken heads of the victims of Papa Nurgle's Plague as a type of grenade. We assume it's the nausea effect that makes them so effective.
One weapon from the Soul Drinkers books was a daemon bound into a gun that fired its own daemonic spawn at enemies.
One option for the Khorne Lord of Skulls, the skullhurler, is a gun shaped like a big skull that shoots smaller skulls. As in, literal skulls. Why yes it is very aptly named.
The Angry Marines fan fiction chapter gives us the following: Door Knob bombs, a Baneblade pistol (a pistol that fires the rounds of Baneblade super tanks), the heavily modified Predator Angrinator which fires Angry Marines, and the Land Raider launcher, a spaceship weapon which fires Land Raiders filled with Angry Marines at other spaceships. It's a measure of how Crazy Awesome this setting is that one's first reaction on hearing about the Baneblade pistol is, "A pistol that fires Baneblades?"
The Doom Diver, a giant slingshot that launches Goblins, the halfling soup pot launcher and the Screaming Skull Catapult. Also the Hellcannon, which loads living beings as the ammunition, then fires their souls.
At least one army featured in White Dwarf a few years back had a stone thrower rebuilt as a Squig Thrower. (A squig-firing cannon would later appear in the Storm of Chaos event thanks to a vocal fansite). Never let it be said that Orcs let the manifest insanity of an idea stop them from trying it anyway.
Ogres don't tend to have a lot of anything (at least, not identical) This includes bullets and cannonballs. So they just make due with anything on hand; a few spoons, a fork or two, a rock, and that gnoblar on your shoulder.
The spin-off game Blood Bowl has Throw Team Mate which allows larger players to throw small ones in place of the ball.
Magic The Gathering is loaded (no pun—okay, okay, pun intended) with cards that shoot or throw odd things. (Most of these cards are at least partly red, the color of chaos, bloodlust, randomness, and some kinds of madness.) Aside from the Hornet Cannon, there are:
Probably any magic-rich setting has its share, but Netheril, being a Magitek sub-setting, featured the netherpelter (a telekinetic gun) with imprisoning, expansive (as in Enlarge), decay inducing, fireball, water jet lashing, and whirlwind (for grounding fliers) pellets as "standard" ammo, though it propelled mundane darts and pellets just as well.
Spelljammer setting has an accelerator, magical breachloading cannon which sucks anything placed in the ammo cup and hurls it with enough exit speed to damage ships' hulls. Grabbing the cup in such a way that some fingers happen to be inside is not recommended. Any and all living "ammo" dies in process — even amorphous fungal mold or slime. Its way of power supply sucks, however.
Perhaps the most disturbing ammunition in DND: arrows with screaming heads on them that distract spellcasters.
In a flavor-text encounter from a Ravenloft supplement, an ally of the Weathermay-Foxgrove twins scores a glancing shot on an unidentified monster with an arrow tipped with multiple needles, each of a different substance. After the skirmish, the twins re-claim the arrow and check which needle is bloodied, thus learning the creature's Kryptonite Factor.
In Exalted, Sidereal Exalted have a charm that lets them fire anything smaller than their arm as an arrow, including shouts - the latter is used as an odd communication technique. They also have a charm that transforms arrows into various things such as wheat, life-force, glass, and boulders.
In the right combo, said charm could allow a Sidereal to fire a barrage of flaming squirrels, or something else even more ludicrous. The game rewards this.
Then you're got the shoulder-mounted cannon that fires giant pearls covered in magical napalm.
There's a weapon which fires solid gold bullets, and propels them towards their targets using the power of the tiny, tiny shrines inside the barrel.
Shards of the Exalted Dream gives Sidereal Firearms the most abnormal ammo of all: nothing. They can kill you without needing to load their gun...or even to have a gun...with Holistic Bullet Methodology.
Hol: Human Occupied Landfill had a flaming gerbil cannon.
For both GURPS and Rifts, There are special rules for making items that use exotic ammo. There's a joke saying a baby wearing a lobster costume in a bucket could be a PC, a weapon, or ammo. Turns out, it's not a joke.
Changeling The Dreaming encourages this kind of creativity when coming up with dream weapons. Still, it is pretty common to simply find a steam powered cannon firing burning coals from its own firebox.
Airsoft guns firing cold iron B Bs are especially lethal.
Scion has Knacks that let you pick up far more than you should, as well as Knacks that give you immense throwing ability. With Epic Strength 10, Strength 5, and the right knacks, you can throw anything in the world. The game notes that at a certain point (say, throwing the U.S.S. Ronald Reagan), damage becomes narrative rather than dice-based.
In the Starship Troopers RPG, there are several weapons that do this, including grenades that can be filled with chemical agents and missile launchers that shoot rockets that unleash walls of fire.
In the Mutant Chronicles universe, the Dark Legion uses things like small, rapidly-multiplying, flesh-eating maggos incased in bullet shells, or bullets treated with a highly infectious desease. The Nazgaroth heavy machinegun fires special bullets that each have a small rune branded onto them to increase their power. If a human soldier is hit with one of those, he will be influenced by the dark symmetry in one way or the other (if he survives).
Armed And Dangerous revels in this trope - aside from conventional bullets and explosives your arsenal also includes:
The Land Shark Gun fires a baby shark into the ground which homes in on the nearest enemy before bursting out fully-grown and devouring them whole.
The Knockout Bomb a wearable boxing glove that flings enemies towards you, allowing you to deliver a Megaton Punch.
There is a bonus weapon in Crimsonland called Splitter Gun. It shots a single bullet that, upon hit, splits into two bullets that spread squarely. The splitting can repeat unlimitedly until all the bullets miss. Bonus points to abnormality for the chance that subsidiary bullets will hit you. Impractical, in fact, but awesome. More "conventional" examples are Rocket minigun and Gauss shotgun.
Though it's not a weapon per se, but through an inventive capitalization on in-game mechanics you can form a reload-powered multi-lateral plasma gun. First, there is an otherwise poor Sonic gun. Frankly, it qualifies for Abnormal Ammo itself (it shoots sound waves), but right now we're more interested in its near-instant reloading. Then, there is a perk called "Angry reloader" that makes you shoot small plasma balls in four directions every time you reload. You combine both, hold the reload button and voil?four endless orthogonal bursts of plasma. Once again, not especially effective, but cool.
In Evil Dead: Regeneration, Ash has the ability to turn into "Deadite Ash". In this form his "boomstick" fires energy bolts. He also constructs a harpoon gun that can attach to his right arm in place of the classic chainsaw, and what can only be described as a rocket launcher shotgun.
Final Fantasy Tactics A2 has cannons, used by two classes. The Flintlock class mostly uses it to shoot his allies to create various effects such as regen or mana restoration. The Cannoneer is more offensive, but can also shoot allies with Potion Shells and Ether Shells.
Final Fantasy VIII also featured Abnormal Ammo in the form of Irvine's Shot Limit. You had your regular ammunition, along with Shotgun or Fast Ammo, but then there's Flame Ammo, AP Ammo, Dark Ammo, and Pulse Ammo. Rinoa uses a crossbow that shoots chakrams. But the real insanity is her Limit Break, in which she stuffs her dog onto the crossbow and shoots it at the enemy. The dog explodes, then runs back to his mistress.
The Gun-Mages in Final Fantasy X-2 are blue mages that use guns to shoot abilities learned from enemies. Shots vary from generic-fireballs to "1000 Needles" to pillars of holy energy. They can even shoot bullets that heal their whole party (White Wind).
Final Fantasy XII features various bullets and arrows that somehow carry with them elemental damage, and several carry status effects as well. They're also completely infinite, unless you sell them, then they're Gone Forever.
Several of the games have the "Coin Toss" ability, which can be devastatingly powerful with enough money on hand.
Metal Wolf Chaos has the shark gun. And the Baseball sniper rifle, exploding bouncing football grenade launcher, Party Cracker shotgun, soap bubble flamethrower, and the homing dragon railgun.
Worms has sheep and homing pigeons being fired from bazookas, the Priceless Ming Vase, the Banana Bomb, the Holy Hand Grenade, and the Old Lady (among the most powerful non-super weapons in the game) as well as the Super Sheep, which is a flying sheep (with a red cape!) which you guide into its target. The super weapons include the "Concrete Donkey", the Super Banana Bomb, and the Flaming Sheep Strike. Let's just put it this way: The more unlikely the weapon, the more powerful it's probably going to be.
Worms Forts: Under Siege has, among other things, a minigun that fires hamsters, a trebuchet that launches a moose and a mortar that fires a bishop.
In Donkey Kong 64 there's the coconut gun, it fires in spurts! (If he shoots ya, it's gonna hurt!) Also, Diddy uses popguns that fires peanuts (these are also used in Super Smash Bros. and Donkey Kong Country Returns), Tiny has a crossbow that launches barbed feathers, Lanky spits grapes out of a blowpipe, and Chunky has a gun that fires pineapples. Funky shoots K. Rool with a rocket propelled boot, and Krusha gets in on the act with a gun that fires exploding oranges.
Half-Life 2 has the gravity gun, which picks up and launches anything and everything that isn't nailed to the ground, so it can be called an everything launcher. Once it gets supercharged, it can pick up plenty of things which are nailed to the ground, walls, and balls of energy from anti-gravity energy columns. Even enemies become ammunition when the gravity gun is supercharged. And that's saying nothing about the sawblades, explosive barrels, cars...
The Half-Life 2 version of the crossbow appears to shoot glowing-hot pieces of rebar.
The Pulse Rifle's secondary fire launches balls of dark energy that cause targets hit to float upward and disappear into the aether. Same effect from the Combine Hunter's exploding flechettes in Episode Two.
Based on Garry's original description of the request forum on the Facepunch Studios forums, somebody made a scripted weapon for Garry's Mod of an AK-47 that shoots rainbow colored babies that can swarm any target and you can eat for 10 health. Yes.
In response, someone else made a version that can also shoot sawblades, and another someone else went the extra mile with a baby SWEP that shoots AK-47's. Yes indeed.
There's tons of these for Garry's Mod, when you come to think of it. There is a "Scavenger Cannon" that can suck up 20 props at once and launch them in any order the player wants similar to Fallout 3's Rock-It Launcher.
Borderlands has relatively tame guns that simply shoot giant globs of acid; as Marcus puts it in a sales pitch, "Is shooting bullets just not cool enough for you? Then get a Maliwan [brand weapon] and light some people on fire!" Then there's the "Carnage" line of shotguns, whose weapon text proclaims, "Holy crap! It shoots rockets!" Again, this is a shotgun. Eridian Weapons are also often esoteric when it comes to ammo — some shoot huge balls of lightning, others fire bouncing acid spheres.
Borderlands 2 saw the Torgue Corporation switch to strictly-explosive ammunition. Which means every Torgue-brand firearm uses some form of self-propelling Gyrojet round, even their shotguns.
It also introduced the spiritual successors to the Carnage shotguns — rocket-firing assault rifles. Vladof, Bandit, and Torgue rocket rifles all fire the same rockets; The Dahl versions are mundane grenade launchers, but the Jakobs versions fire small cannonballs.
A later addition to the game was the Carnage shotgun — a rare Pearlescent weapon that's much more powerful than its counterparts in the first game.
E-Tech weapons use Eridian technology to turn bullets into what can only be described as "stuff that ain't bullets." What exactly that "stuff" is depends on the weapon type, and sometimes the manufacturer — E-Tech pistols fire spikes that stick in a target and shatter after a few seconds, for instance.
In the Tiny Tina's Assault on Dragon Keep DLC, there's the SWORDSPLOSION!!! shotgun, which is a shotgun that fires exploding swords. Said swords explode into other, smaller swords that also explode. And if you get a SWORDSPLOSION!!! with the "Casual" prefix, every shot from the gun fires three initial swords, which also explode into three smaller swords.
Doom 3: Resurrection of Evil has a weapon like the gravity gun from Half-Life 2. The main difference is that the Grabber in Doom can only hold objects in its field for a couple of seconds before being released.
South Park for Nintendo 64 has...yellow snowballs. The most powerful weapon is a cow launcher. There are grenades that look like Terence and Philip dolls; they fart to explode. The game's equivalent to a sniper rifle is a chicken that shoots eggs. You even aim it through a little notch in its tail feathers!
Warcraft III has the Undead Meat Wagon, a catapult that launches corpses. Notice that this is not as far-fetched as it seems; there are real instances of armies stuffing their catapults with corpses, as you can see in the appropriate section below. (Indeed, you can even upgrade the meat wagons so the corpses they throw spread disease.) The Night Elf Glaive Thrower from the same game is a siege weapon that throws blades so sharp at such high speed they can cut down trees.
In the Cataclysm expansion for World of Warcraft, one of the goblin quests in the Twilight Highlands requires you to shoot an antiaircraft gun that's been loaded with anything the goblins could find lying around — old shoes, inflatable pool ponies, you name it. As with all pieces of goblin technology, this improvised ammo still manages to explode on contact with its target.
The Wrath Of The Lich King expansion brought out the Isle Of Conquest Pv P battleground which had (among many fun vehicles) Glaive Throwers (which fired big spinny things of doom) and quite small, unassuming catapults...that fired THEIR OWN DRIVER (as a way to get troops inside the enemy fortress before breaking the gates).
Another Cataclysm quest involves attacking an enemy-held war zeppelin. By being shot out of a cannon at it! When asked why, if he has a cannon, he doesn't just shoot cannonballs at them, the quest giver replies, "No way! They'll see that coming..."
There's also the Flintlocke's Woodchucker gun attachment, which periodically shoots a "random rabid critter" at your target, in homage to Flintlocke's Guide To Azeroth.
"'slike a wee angry bullet wit' teeth, son."
As noted in the Zero Punctuation review of the game, Painkiller has the Electrodriver, which does indeed fire shurikens and lightning. There's also the stakegun ("penis extension gun", in Yahtzee's parlance), which shoots "sharpened telephone poles".
The fanmade sequel Overdose includes a number of these, to its detriment. Some examples include a crossbow that shoots skulls, a shotgun that shoots (fragments of) skulls, and a knife that shoots more SKULLS.
Cave Story has the bubble gun (surprisingly powerful), and a throwing knife whose fully-leveled form launches a knife-wielding ghost (very powerful!). There's also the highest-level form of the Nemesis gun, which actually gets weaker as you level it up; it shoots rubber ducks.
One of the bosses, Monster X, shoots fish at you. Or rather, homing missiles shaped like fish (complete with eyes).
In Oddworld: Stranger's Wrath, the main character has a crossbow that shoots a variety of wildlife, including: enemy-taunting chipmunks, giant armored pillbugs, exploding bats, and little bitey alien things perhaps best described as rabid carnivorous tribbles.
Crusader gains a couple of Abnormal Ammo guns in its second installment. The crystallizer shoots a weird cartridge that inhibits its targets' molecules; since motion is heat, the shot is described as being comparable to "several minutes' exposure to absolute zero". The result is a statue in an agonized pose, which you can then shatter. The liquifier shoots a classified catalytic compound which breaks down molecular bonds, reducing the target to a puddle of its base elements. There's a neat, brownish, human-shaped cloud when it hits a target, and then all that's left behind is a splotch of green goo.
Fallout 2 has the Solar Schorcher, a solar-powered gun. You can only reload it outdoors.
Fallout Tactics has a water gun. You think it's a joke weapon...until you come across jars of acid.
Fallout 3 has the Fat Man, a launcher which launches a mini nuke at its target, abnormal in the sense that the ammo is so heavy that if you fire it parallel to the ground (instead of at an angle), the nuke will go a very short distance and catch you in its blast radius. Clever characters can track down the Experimental MIRV version which shoots 8 mini nukes at once in a random scattershot pattern.
Fallout 3 adds a gun that shoots railway spikes, a gun that shoots poison darts (as in the sort you throw at a dartboard) and a gun that can shoot any trash the player can find. You haven't lived until you kill a Super Mutant by launching a teddy bear at them and blowing every limb off their body.
The Dead Money DLC introduces the holorifle, which fires a cluster of high-energy holograms at the target.
God of War has the Minotaur Boss, a heavily armored behemoth that you have to stun before resorting to twisted means to execute it: You run back to a platform and fire a flaming log/stake at it, cracking the armor and eventually nailing it to the door it emerged from.
It also has the Atlas Statue. In order to get to an objective, you have to risk life and limb plowing through Undead Mooks and platforming to wind up the statue, which then throws the Earth it bears down the hallway and through the wall that impede your progress.
The Unreal Tournamentseries has mostly-conventional Standard FPS Guns, the impact hammer aside, but one of the more interesting ones is the GES Biorifle, a goo gun which you can either slime someone with or lay down explosive poisonous traps with.
The goo gun doesn't appear in Unreal II: The Awakening, which instead has something much weirder: a gun that shoots spiders. Primary fire covers a target in spiders, which doesn't kill them very quickly but does make them run around screaming "Aaaaaaagh get them off meeeeeeee!" For this reason it may well be the second-most fun weapon in the game. Secondary fire shoots a glob of biomass that turns into a big spider when you hit it with the primary fire; the spider then follows you and attacks your enemies. Then there's the BFG that shoots miniature black holes.
The entire Unreal series is very friendly to weird weaponry, thanks to the way the engine works. Open up the editor, find a projectile-launching weapon, substitute the class name of the bullet with that of most other entities in the game world, and... voila, a Stinger that fires rockets, or ASMD blast-balls, or grenades. Or rabbits.
One weapon in the "Contrabobo" stage of Abobos Big Adventure is a gun that shoots Lemmings. Not real lemmings, by the way: the green-haired, bipedal critters from the eponymous game: if they hit an enemy, they bounce off and walk around for a while before exploding.
Star Wars: Dark Forces 2: Jedi Knight used a similar idea: The alternate fire on the rocket launcher made the spider-shaped rockets grab onto objects and wait for a few seconds before going off. Instead of just blowing up the enemy, you got to see them run around with an exploding spider-bomb on them. So, so much more fun.
A wild magic surge in Baldur's Gate II could result in a cow dropping on the target. Also in the game was Jan Jansen's Flasher Master Bruiser Mates, used (naturally) with Jan Jansen's impeccably stylish Flasher Master Bruiser crossbow. They were stun bombs, but they looked like skulls.
Planescape: Torment features a high-level spell called Mechanus cannon. It's a pretty generic cannon... fired from a different plane of existence, through a portal, opened five feet from your enemy's head.
It also features a few strange projectiles for Nodrom - Rule of Three bolts with spring-loaded pyramidal heads, Bolts of Wincing which look like bladed U's (the name comes from what observers do when the bolts go in...or are pulled out), and bolts with sponge-heads (the sponges are full of acid).
Tyrian had several "hidden" ships you could play through a "super arcade mode" by using a cheat code. The Ninja Stealth ship had several ninja-themed weapons, including poison bombs (against other ships?), "starburst" (a weapon that threw starshaped chunks of hot metal out sideways from your ship—usable as a secondary weapon in the normal game, not much good as a primary), and shuriken, which when fully-upgraded resulted in a massive forward field of shuriken shot from the front of your ship. Taking the cake, though, had to be the Foodship Nine Supercarrot, which used entirely food-related weapons, from a banana gun that threw out a tree's worth of explosive bananas per second, a secondary banana bomb launcher, a hotdog-with-optional-mustard-spread, and an orange...thingy...that created a whirling circle of oranges.
Wizardry 8 features the gadgeteer class. This class comes with a unique rifle, whose choice of potential ammo expands as you level up. It starts able to only fire rocks and pellets, later gaining the ability to shoot daggers, arrows, axes, swords, lightsabers, grenade-like potions...
RuneScape has a number of these, many of which use living creatures in some way or another. It's a good thing there's no PETA in RuneScape...
The Fixed Device shoots dyed toads.
Salamanders use up tar mixed with various herbs as the ammo for them to shoot flames out. Yes, you hold the salamanders in your hands.
Crystal bows "use" no ammo. They weaken as you use them because you're essentially firing little bits of the bow itself at things.
Chinchompas are small, highly explosive animals. You throw them at people. They may not be shot out of anything, but they are fun to watch.
With the oddball aura active, the dwarven multicannon would fire squids, beers or cabbages instead of cannonballs.
Scorched Earth features a type of shell that explodes in a 100-300 feet sphere (well, circle, it's a 2D game) of dirt. Apparently dirt is very compressible. It also features three different families of dirt-destroying weapons.
Mass Effect 3 continues the trend. We knew about twoweapons that made use of this trope before the game was even released. We can now add a krogan shotgun that shoots spikes designed to make enemies bleed out and a geth sniper rifle that fires ferrofluid.
Tribes: Ascend gives you a "Blue Plate Special" award if you kill someone in mid-air with a spinfusor disc.
Drawn to Life has a gun that shoots snowballs for the first world. For the second world, it's tinkered with so that it shoots exploding acorns.
In the third world, it shoots starfish.
In the second game, you can make the ammo WHATEVER YOU WANT IT TO BE.
Many of the games in World of Mana series had a system of cannons, located all around the world, that fired main characters very, very high in order to transport them elsewhere. Needless to say, there wasn't any fall damage, so it was way superior to walking through half the world to player's next destination.
Ratchet & Clank: Amongst the weapons included in the game we have guns that will turn any enemy into various farmyard animals, a land shark gun, a gun that fires heat-seeking servings of vindaloo curry, a mine that spits out bees, and the suck cannon, a weapon which sucks up your enemies and fires them as ammo. There is also a gun that shoots black holes, and grenades that turn into little robots that themselves have guns. Finally, we have the gun that fires tornadoes, complete with lightning storms, wrist weapons that launched sentient and powerful blobs of slime, and capping it all off with a bomb that makes any enemy - from wandering creatures to NPC's to bosses - start dancing to disco music, each one having a distinct dance.
Half-Life spinoff Gunman Chronicles has a gun that shoots a variable amount of acid, basic and neutral liquid in form of globs. The amount of the three liquids is user-selectable, resulting in different effects and different ammo consumption. The bad thing is that such a user interface is obviously very fiddly, so players tend to set the gun to its most destructive setting (full acid, full base, half neutral) and leave it at that; the good thing is that, in contrast to other such weird guns (such as, say, the aforementioned biorifle from Unreal) smart players actually use the chemical gun.
The mod Rocket Crowbar changed the shotgun to fire screaming scientists who flew towards the target and exploded on contact.
In Super Mario RPG for the SNES, Bowser's Hurly Gloves weapon, described as "A classic Mario-toss attack," is just that: Bowser tossing Mario comedically at enemies. When Mario is unable to be thrown (due to death, absence from the battlefield, or the mushroom and scarecrow status ailments, etc.), the Mario doll first seen in Gaz's house is thrown (for the same amount of damage).
Geno's Star Gun, which happens to shoot little stars.
Almost all of Geno's weapons are like this: from firing his hands to canon balls out of his elbow.
Super Mario Bros. has been doing this for a very long time with the Bullet Bill as well as the Bo-bombs.
In Redneck Rampage you find dynamite, a generic tossed explosive. Later, you upgrade it to a rocket launcher by finding a crossbow. Then you find a chicken... strap the chicken to an arrow, jam dynamite up the egg-hole, and now you have a chicken-guided missile launcher complete with 'b-gawk!' sound effects and drifting feathers. Also, while not exactly abnormal ammo, you kill a big alien and take its gun... which is cyber-grafted to its arm. You fire it by yanking on dangling tendons.
In Oni, some of the more advanced weapons included a sniper railgun that fired slugs of frozen mercury, and an energy weapon that fired a grenade, which released a Life Energy absorbing psychic entity, that would move from target to target until it was done feeding, including attacking the player if it was fired carelessly. Each of those took the same generic ammo clips as the other projectile and energy weapons.
Rise of Legends has a number of these, especially from the Steam Punk "Vinci" factions. Standouts are the Doge Cannon and Doomcannon, both of which can fire a poison gas, shrapnel, or explosive shell; or the ability of certain heroes to fire flare rockets that turn into so-called "Holdout Towers".
In Command & Conquer: Tiberian Sun, GDI Grenadiers throw bouncing explosive frisbees instead of normal grenades. Command & Conquer: Tiberium Wars gives them more oval-shaped grenades which can lock onto and guide themselves to far-away targets, particularly ones holed up in abandoned buildings - one Grenadier getting close enough is all you need to clear the entire building and place your own soldiers in it.
Xenogears: Citan built the Buntline, a Gear that can transform into a giant gun. Its ammo? Its own cockpit, pilot and all.
One of the attacks one can learn for Bazookas in Makai Kingdom involves stuffing your opponent down the barrel and firing them out.
Toe Jam And Earl has you using tomatoes as your primary attack. The first sequel has bottles. No, they don't break on enemies and hurt them; they open and suck enemies in, rather like the ghost trap in Ghostbusters.
In Dragon Quest Heroes Rocket Slime, the mechas can shoot anything from missiles, to swords, to holy water, to statues, and NPCs and enemies. In fact, any item you collect in the game can be used as ammo.
One of the first moves learned in Banjo-Kazooie is how to launch blue eggs out of Kazooie's mouth.
There's Mr Patch from the sequel, whose main attack is to spit exploding beach balls at you.
Kazooie's egg-shooting ability is taken to a ridiculous extreme in the sequel, in which, in addition to the standard blue eggs, you get fire, grenade, ice, and "clockwork kazooie" eggs. The same game's multiplayer mode adds proximity eggs, which latch onto walls and explode whenever someone gets close enough.
The Turok series has the bore-gun which fires nanobots of some type which slice apart the enemy into bite-sized chunks.
Portal has a gun that fires interlinked portals. Firing directly at a turret won't even nudge it, but there are numerous ways to use the portals around the turrets to disable them. Speaking of the turrets, they don't shoot ordinary bullets. They shoot the entire bullet (that's 65% more bullet!).
Hellgate: London has guns that shoot bees, exploding lightning balls, and horrible clouds of green plague gas.
The Gun Del Sol from Boktai shoots solar energy in some solid form - there's bullets, grenades, and seeker missiles, but the Dragoon is a solar-powered flamethrower! Yes, a Solar Gun that kills enemies with sunfire.
Pocket Tanks is an extreme example of this trope. Tanks there can shoot: *deep breath* ...dirt, pop corn, rubber, bees, roman candles, sawblades...FLEAS!...star dust, water, tornadoes, coal, fireflies, glue, chalks and so on.
Puzzle Quest: Challenge Of The Warlords has the Gobshooter enemy - a catapult that uses goblins as ammo (Destroying a random gem on the board for 20x effect). The funny thing is that the Hurl Goblin attack is learnable!
Zombies Ate My Neighbors. You start with a squirt gun full of holy water that can kill zombies. You also can attack with: tomatoes, popsicles, silverware, dishware, six packs of soda (That explode like grenades), footballs, fire extinguishers, weed trimmers and an alien ray gun that fires bubbles. The only "normal" weapon you obtain is the bazooka.
Anarchy Online starts you off with a weapon with infinite ammo. This is handwaved as being a gun which fires tiny nanotech-created replicas of itself.
The SMG in Deus Ex: Invisible War has an alt-fire which launches flash grenades. By contrast, the Widowmaker SMG (every weapon has a special variant) has an alt-fire which launches spiderbots. Spiderbots are far from deadly, until your enemy is surrounded by twenty or so.
This trope features very heavily in the ending of Sakura Taisen 3.
Revolution X, the Spiritual Sequel to Midway Games' Terminator 2 - The Arcade Game, had the player armed with a machine gun...as well as a launcher that fired exploding CD's. As a powerup, the player could also upgrade to Laserdiscs!
The Angelic Rifle in Baroque shoots tiny winged babies that are living, sentient incarnations of pain.
Minecraft lets you uses dispensers as turrets. While they can "fire" out anything you stuff into them, most of it just falls down harmlessly. Though you can have them fire arrows, incendiary ammunition, potions of all kinds (including healing ones), snowballs, and eggs. Eggs which may spawn baby chicken upon hitting the ground. Most of these can also be thrown by hand.
The helper character gets pretty standard weaponry (Hyaktaro's Ryu rip-off notwithstanding), except for the unused Glen Achilles, who apparently fires spinning, exploding Heavy Machine Guns.
The Metroid series has the following: a gun that shoots superheated magma grenades (Magmaul), supercooled plasma (Judicator), killer neutrinos (Shock Coil), miniature nuclear weapons (Battlehammer), holy planet energy (Light beam) and a miniature star (Sunburst), anti-energy (Dark beam) and a portal to hell (Darkburst), matter-antimatter (Annihilator beam) and the sound barrier (Sonic Boom), sentient goo in energy form (any phazon weapon) and the Stacked beam, which contains the plasma, ice, and wave beams at the same time in a six foot wall.
And if we count glitches, there's also the Murder Beam, which is best described as a wall of solid PAIN AND SUFFERING.
Can be modded into Dwarf Fortress quite easily, since the game can support up to three different types of arrow, crossbow bolt and (presumably) blowdart each. Anything can be thrown in adventure mode. One rather famous story is how a player decapitated what is essentially a living statue of liberty with a rabbit.
On the subject of Might and Magic, Might and Magic VI has a unique weapon, Artemis, which is a longbow that shoots lightning bolts. It also has the "of Carnage" enchantment, which only applies to bows, and makes them shoot arrows that explode.
Also, Liches from the Heroes of Might and Magic games throw clouds. Of death.
And Magogs from Heroes of Might and Magic III throw fireballs.
In Vangers there is a basic machinegun that makes ammo out of dirt and water. Also a gun that shoots money.
Prey's alien world is chock full of annoying crab-like three-legged things. They don't really do anything other than walk around... and explode, vigorously, should you tear off their legs. Or you can stuff them into a pneumatic launcher, giving the local equivalent of a grenade launcher. Talk about live grenades.
The acid gun, a shotgun that sprays acid instead of pellets, and launches an acid-filled tube with the secondary fire.
In Red Alert 3: Paradox, the Mediterranean Syndicate's standard weapons fire Gyrojets, little finless rockets that accelerate as they fly, doing more damage the farther away they hit. They're based on an actual weapon described below, and the numerous flaws listed are the reason why they never made it to mass production in Real Life.
The PlayStation game Terracon features the "Genergy Gun". In combat it's a fairly ordinary energy weapon. The gimmick is that the game also features coloured wireframe "meshes", which turn into solid objects and functional devices when shot with enough Genergy.
The Blood series has the Life Leech, a staff with a one-eyed skull that launches magic fire at enemies, sucking the life out of them and healing the player. In the first game, its intended ammunition was trapped souls.
In Paper Mario: The Thousand-Year Door, Magnus von Grapple 2.0 has an attack that sucks up the audience and then fires them like a machine gun. To make matters worse, this is one of the strongest attacks in the game if you don't guard correctly.
XCOM Interceptor features mostly normal weapons: you start with lasers and missiles, upgrade to more powerful lasers and missiles, eventually get plasma weapons, and then develop the psi-beam, which is a laser that shoots mind-control beams.
The LEGOPirates of the Caribbean game has a scene where the Spanish fire a pig from a cannon to destroy the Fountain of Youth. Since this is a LEGO game and everything is smashable, this is more successful than the film example of firing a monkey.
In Jables's Adventure, your only weapon is the Hurricane Pistol, which fires a concentrated air blast.
Rockman 4 Minus Infinity has the Spark. Manbow. Normally, it is just Mega Man creating a lightbulb with his to shock his foes at point-blank range. Release the fire button and it becomes a projectile.
Terraria brings the Sandgun.It does exactly what you expect it to do, it shoots sand blocks. It can be used as a direct fire weapon, or block off an area from a distance.
There's a few other strange ammo types. Once you reach Hardmode, you can craft cursed flame rounds and crystal fragmentation bullets. Crossbow users, meanwhile, have the Holy Arrows, which drop stars on whatever they hit.
The Angry Birds use themselves as ammo against the pigs. They even come in different varieties, including an exploding bird.
Bulletstorm has a gun that shoots explosive bolas (the Flailgun) , and another that shoots rocket-propelled drillbits (the Penetrator). The sniper rifle fires tiny guided missiles.
League of Legends has the usual ricochet bullets, homing bullets, bola nets and giant knives. Urgot's Butcher skin shoots homing chainsaws.
In Iji it is possible, through the use of prolonged self-abuse, to find a Banana Gun. And it's the only human-made weapon in the whole game.
In Hyper Princess Pitch, bricks are your basic ammunition. Your other weapons are a rainbow blaster and an ice ray.
In Kid Icarus: Uprising, some of Pit's odder weapons can fire things like bouncing pawprints, jumbled chunks of skyscraper, or crescent moons
Dragon Age II's Mark of the Assassin DLC has a villain named Duke Prosper as its Big Bad. He is also the final boss fight; he uses an automatic crossbow that can shoot either arrows or a strange green goo. The strange green goo does no damage by itself...but as the cutscene just before the boss fights demonstrates on the poor, unfortunate Salit, Prosper also has a pet wyvern named Leopold that has been trained to relentlessly chase and attack-to-kill anyone Propser has first shot with this green goo. When he uses it in battle, he will either shoot one of Hawke's companions with it, so Leopold will chase that companion leaving itself open to an attack from Hawke, or more frequently Prosper will shoot Hawke with the goo, making it necessary for Hawke to spend his/her time running from Leopold until the goo wears off.
An optional quest in Gears of War 3 lets you get your hands on the Cluckshot, a rocket launcher that shoots exploding chickens.
This is standard for any wielder of firearms in the Tales Series.
Blood Crusher 2 has numerous randomized ammunition options, from standard bullets to ninja stars and hordes of pissed off bees
Kingdom of Loathing has a number of ranged weapons that fire unusual ammo, like the goulauncher (a crossbow that fires goulash made from ghoul meat) and the potato pistol (like a spud gun, "but smaller. And greasier.")
Pastamancers can cast spells that pelt enemies with ex-girlfriends (which deal ice damage), pin-ups, nudity itself, and even something that's censored out.
Awesomenauts brings us Derpl Zork. When asked what form of devastation should be issued forth from his mighty combat walker, he simply drooled and said "I wuv cats". Thus came the holo-cat cannon. Yes, you read that right. Hard Light cats.
The Wonderful 101 has the eponymous heroes group together to turn into various firearms and then fire themselves from those weapons.
In Saints Row The Third, the Boss can upgrade some of his/her weapons to fire incendiary or explosive ammo. There are also a number of DLC weapons such as the Octopus Launcher, which shoots ocotpi that mind-control your enemies into attacking one another before self-destructing, the Genki Manapult, a truck that sucks up pedestrians and shoots them out of a cannon on the back, and a shotgun that fires chum in order to entice a killer sewer-dwelling shark to burst out of the ground and attack your opponents.
In Quackshot, Donald's arsenal consists of a plunger gun, exploding bubblegum bubbles, and a powerful scattershot popcorn. The villains' ammunition includes tomatoes, toxic gunk, and beehives.
Fate/stay night introduces two Servants of the "Archer" class. Both of them shoot swords rather than arrows. And not just any swords, but legendary swords imbued with immense magical power. Which they proceed to shoot at their targets by the hundreds.
The Furtive Polar Bear in Tales Of The Blode Episode 4 defends his North Pole lair with a gun that fires kittens.
At one point in Red vs. Blue, Caboose's gun is revealed to be loaded with crayons rather than bullets, although he never fires it like this. Comes in handy when he and Tucker need to draw visual aids to teach Crunchbite the Alien English.
It's Walky! has the monkey cannon from the Monkey Master.
Dreamleak features a quadruple pie thrower. Interestingly, it was not used as a weapon but as a clay pigeon launcher.
This from Sluggy Freelance shows an Inflatable Rabbit Decoy Inflatable Cannon. The repetition of the word "Inflatable" is not an error.
This shows a ray-gun that can be set to "Stun", "Kill", "Mashed Potatoes", and "Olives", the last of which is used.
To fight vampires, Riff developed an auto-staker; a Gatling that fires 1k wooden stakes a second. Awesome to shoot, a nightmare to reload.
Riff also developed "sleep chaff", a flurry of little razor discs with a tranquilizer gel center.
In the Guntron Alliance Force strip of The Perry Bible Fellowship, we are presented with a Combining Mecha Gun that shoots the vehicle of the blue member of the group as a bullet. No wonder the green guy looks pissed as he takes his place in the gun chamber. They must go through many members that way...
Mac Hall implies there's two kinds of "Monkey Guns" — one that's just a run-of-the-mill gun used for shooting at monkeys, and another that was a gun that shot monkeys ''out of it''. Ian is told that they didn't have either one on hand.
Fighter talks about a weapon firing sword-beams. A constant stream of laser-powered swords.
There is also the Giant Cannon. No, it's not just a really big cannon. However, it has to be somewhat big to be able to fire giants.
The World of Warcraft parody strip Flintlockes Guide To Azeroth uses this as a running gag. To make matters worse, most of the ammo is alive at least until the time of firing. He killed someone in one hit using a supersonic woodchuck.
An upgraded version of "tha Chuckshot", known as the "remote backstab", involves firing Lowping, the party's rogue, at the target. After impacting, and presumably totaling anyone who gets in the way, the rogue will backstab any survivors. It works.
Bob the Angry Flower has such a vast collection of ray guns it is inevitable some would fit this trope. He turned back a crowd of his enemies with his Donut Ray, while the Seahorse Ray was mostly used for a cheap laugh.
In Zokusho Comics, while [[Serge's]] "Phantom Shot" provides him with an infinite amount of ordinary ammunition, his revolver, Lucky Seven, fires magical bullets. He tends to prefer Fireballs.
A Beginners Guide To The End Of The Universe has the protagonist create an "autoflintlock", which is able to shoot anything that can fit even halfway into one of its barrels, though only items the size of a revolver round can be stored in its ammunition chambers.
The standard Genocide Man handgun is a railgun that shoots nickel-plated plastic needles, not really that deadly by themselves so they're tipped with Sarin-M.
Metroid: Third Derivative has some. Some notable ones include the Kinetic Beam which only does damage should it's target collide with something else, the Phase Beam which has mysterious space-time properties, and Mega Missiles that nuke entire rooms (including the user too).
Trident uses a wrist-mounted gun that fires little miniature tridents.
Chuckles the Clown uses a "pie-shot"—a slingshot that fires bannana cream pies and has a pistol that fires ping-pong balls. The pies deliver a knock-out drug and the ping-pong balls explode.
Cute little Generator in the Whateley Universe has a linear accelerator gun which fires Tasers, explosives, and sticky nets of webbing. But her bracers are even better. While they appear to fire different kinds of missiles, what they really fire are psychokinetic copies of Generator herself, which then hold and direct the missiles.
Guns in Chaos Fighters-Route of Sea can fire swords, lances and feathers.
For your viewing pleasure, the RPC M1B◊ Rocket Propelled chainsaw Launcher.
The title heroes of The Mighty Ducks fire weapons loaded with exploding... pucks.
Spidey gets to fight a massive battle across NYC's rooftops against the Green Goblin and his Hyperspace Arsenal, some pumpkin-bomb-launchers camouflaged as watertowers, and hordes of pumpkin-masked Mooks wielding bazookas that fire large metal slugs sprouting tiny spikes all over in mid-air.
The Simpsons had an accidental version of this when Homer joins the Navy Reserve. Through his general incompetence Homer ends up firing their captain out of a torpedo tube, which then hits another sub. The men on the other sub remark that "We've been hit by an officer!" When ordered to return fire, the men are about to grab their officer who stops his men and says "Not me, a torpedo!"
Another instance is when Homer signs up for the Army. He is assigned to be the leader of the enemy in war games. While the Army uses live ammo, Homer's army has bubbles for ammo.
The make-up gun Homer invented. "Homer, you've got it set on 'whore!'"
As Joan of Arc, Lisa suggested the French army use bigger soldiers in their catapults, or better yet, rocks. The soldier who was about to be fired doesn't know how to feel.
Wild West C.O.W.-Boys of Moo Mesa had guns that fired tiny sheriff badges, cactus spines, vegetables, spider webs, chunks of dirt, and everything else except actual bullets.
The Black Raven from Wakfu fires eggs that hatch into mini ravens.
An episode of Jimmy Two-Shoes had a gun that shot some small, unknown creatures.
Futurama's "Godfellas" has Leela accidentally using Bender as a torpedo. In "Fun on a Bun", an army of cavemen takes out Zapp Brannigan's ship by catapulting a saber-toothed cat through the window.
In the Camp Lazlo episode "Mascot Madness", Edward's mascot the Duke of Lice has a lice cannon that shoots... Well, you figure it out.
In The Problem Solverz episode "Fauxboro", Alfe and Roba construct a Gatling gun that fires root beer.
On The Ren & Stimpy Show Stimpy is reading the story of "Robin Hoek." He can't remember what Robin fired in the air with his bow but thinks it was a melon. He then believes it was a chicken, which Ren is prepared for as he is wearing a helmet this time. At the last moment, Stimpy surmises it was a moose.
In the Rockos Modern Life episode "Sailing the Seven ZZZ's" Mr. Bighead thinks he is a pirate while sleepwalking. He uses his laundry machine as a cannon and fires several items including a TV set, a toaster, and a blender.
In Slugterra, people shoot tiny cute creatures called slugs. When the slugs reach 100mph they change into their true form and have some unique effect before quickly reverting back to slug form. They're Mons as bullets.
Motorcity features a gigantic blinged-out tank more akin to a land-going battleship, owned by the insanely wealthy car collector known as the Duke of Detroit. Its monstrous gold-plated main guns fire over-sized stretch limousines as ammunition. Each cannon has its own magazine of luxury cars to blast forth, thus perhaps demonstrating the ultimate in weaponized excess.
The Madagascar short film ''The Madagascar Penguins in a Christmas Caper" used the penguin Rico as a gun, firing the contents of a bowl of peppermint candies at Killer Rabbit (or in this case, poodle) Mr. Chew.
The SWAT Kats' arsenal includes machine guns that shoot quick-drying cement, as well as missiles with such functions as electricity, wire cutters, drills, sonic blasts, nets, and buzz saws.
BIONICLE has several examples, but one of the first and best is probably the Kanoka, which are essentially superpowered frisbee disks.
There was also an arc that took place underwater; some of the good guys used air bubbles as ammo (toxic to waterbreathers) while the bad guys shot vampiric squids.
Near the end, the ammo of choice was Thornax, a kind of fruit. Hey, don't laugh; would you like to get hit with a coconut at high speed? A spiky, potentially explosive coconut?
An editor's error in a Polish video game magazine Top Secret resulted in a description of a "grenade-launcher launcher". Nifty.
With Second Life having tons of user created stuff, there are certainly guns out there that shoot weird stuff. There's a gun that shoots more than 15 Red Shells that seek out other avatars nearby and makes a big firework-like explosion upon impact. Then there's another gun that shoots Stars by the truckload and all of them have the starman theme playing at the same time, which sounds freaky when the sound gets distorted due to how fast they fly when shot out.
Also Watermelon Rifles, Cat Cannons, Heart Crossbows, and a dildo gun.
Years ago, one of the Star Wars fan boards out there on the internet had developed a cannon that shot Ewoks. Sadly the schematics or specs or backstory are no longer available, but they were even developing different types of ammo for said cannon.
There was a discussion on GameFAQs once regarding the usefulness of detonating FTL cores of ships in the Halo universe. Cortana was a fan of it because of the massive explosions.
During the nuclear test sequence Upshot-Knothole in 1953, test Grable fired an 11-inch nuclear warhead from a specially constructed artillery piece known as "Atomic Annie." This is fairly unconventional in itself, but more so if it's noted that the W9 warhead used was of similar construction to the "gun-type" "Little Boy" bomb dropped on Hiroshima. This therefore marks perhaps the only time in history that a gun has been fired out of a gun. The design of "Little Boy" featured a core of barely sub-critical reaction mass, with an additional radioactive slug stored separately with a gunpowder charge. At a certain altitude the gunpowder would be detonated, propelling the slug into the main core, causing it to reach critical mass and explode. Thus, the Grable test featured a bomb, set off by a gun, fired from another gun.
Aside from the rather specialised Atomic Annie piece (and its lesser-known Soviet counterpart), if one were to look-up a list of American, Soviet/Russian, NATO, and probably even Chinese artillery pieces post-1965 and pick any tube (as in a gun or howitzer, not rocket) piece of 150mm or more on that list, there is a 99% chance that artillery piece had tactical nuclear artillery shells designed for it. Even the US's Iowa-Class Battleshipsmain 16-inch guns received nuclear artillery shells.
Grapeshot. It is basically charging a muzzle-loaded cannon with iron and steel junk, pieces of chain, pebbles and anything shootable and shooting it against a charging enemy. The range would be less than that of a regular cannoball, but it could make horrendous damage at close range. Usually grapeshot was the last measure against an oncoming enemy, and if it did fail to stop the enemy, the gunners would spike the cannons and flee.
Corpses have often been used as catapult ammo. In fact, the Black Plague is thought to have originated in 1346, when the Mongols launched bubonic plague-infected corpses over the walls of Crimean city of Kaffa (now Feodosia) that was besieged. Six years earlier at Thun l'Eveque, decomposing animals were used as ammo. The last known incident of using plague corpses for biological warfare occurred in 1710, when Russian forces attacked the Swedes by flinging plague-infected corpses over the city walls of Reval (these days called Tallinn).
In 204 B.C, Hannibal of Carthage had clay pots filled with venomous snakes and instructed his soldiers to throw the pots onto the decks of Pergamene ships.
Some of the older types of cannonballs include grapeshot, exploding cannonballs, and chainshot, which was two cannonballs chained together, usually used to destroy sailing masts or sails themselves. Or just fire a big wad of chain out of a cannon. It will tear a man to pieces. An improvised abnormal ammo load was "Langrage", which consisted of any old junk that was available - essentially turning the cannon into a very large shotgun, firing nails, broken chain links, and other assorted rubbish.
The word "shrapnel" comes from the British artillery officer Henry Shrapnel, who invented a cannon ball that would explode in mid-air unleashing a rain of musket buckshot.
In The American Civil War, when ships still used wooden hulls but steam power became common, gunners sometimes heated their cannonballs red hot using the engine furnace before firing at the enemy. Using "hot shot," as it was called, could easily set the target on fire. Captains used this sparingly, since mishandling the red hot cannonballs could easily burn down their own ship
"Hot Shot" is a couple hundred years older than that, it just was only used by fortresses—most of which would have a ready furnace, and no hull or sails to worry about. Steam just made it ship-deployable.
An early hobby for many tinkerers is designing such weapons. Probably the most common one is the potato gun. Followed by the marshmallow gun, a more contemporary example.
And then there are the famous demonstrations/competitions of the physics of catapults and trebuchets, where people use them to fling watermelons, pianos, cars, and sometimes people.
Slings and slingshots. Seeds, pebbles, coins, ball bearings, screw nuts, bone pieces - anything that can fit on the pouch goes.
Also not meant to be lethal - a Japanese company sells air guns that shoot teddy bears with parachutes. For weddings, apparently.
Japanese san-shiki ("beehive") anti-aircraft battleship shells, which could best be described as 18 inch (457 mm) shotgun rounds.
The incredibly awesomeDragon's Breath shotgun round fires a gout of flame about 20 feet long for about 3-5 seconds from a manually operated shotgun. The Dragon's Breath shotgun round does a lot of damage to the barrel of the shotgun, making it Awesome, but Impractical for most situations.
For one particularly crazy example, the Taser XREP, which is miniaturized taser fitted within 12 gauge shell for long distance wireless delivery of electric shocks.
Large-bore shotguns are sometimes loaded with rolls of coins. Makes a big, big hole at close range. Supposedly, during Stepan Razin's rebellion one of their supply squads reported about being caught by tzar's troops and having to "buy off". And clarified that they quickly ran out of bullets, but still had lots of coins... and powder.
Uruguay gained its independence from the Spanish by, in one battle, firing rock-hard balls of Edam cheese out of its cannons at enemy ships after its ships had ran out of normal ammo.
Used at many a sporting event: the infamous T-shirt cannon.
The SPP-1 pistol and the APS underwater assault smoothbore are specially designed underwater weapons with their own underwater ammunition — long and slim bullets. Yeah, it's a real nailgun. Modern ADS uses both standard issue ammo for AK-74 (in the air) and new underwater cartridge that looks like the same 5.45x39 — but its bullet continues all the way to the bottom.
Before WWII, the US fielded battleships fitted with special cannons to launch seaplanes as spotter aircraft. (The aircraft rode a sort of sled puched by the explosive charge, so it isn't quite as cool as it might have sounded there.)
The M712 Copperhead, which is sort of like an artillery shell - except it's really a laser guided killer robot!
Not a weapon meant for people, but one of the ways they test jet engines, windows, and various other parts of the plane for durability against bird strike hazards is to use a specially designed cannon that fires whole chickens. It's important to remember to defrost them first, though.
The Gyrojet line of weapons must be mentioned here. Designed and built in the 1960s they fired gyroscopically-stabilized 13mm rockets looking much like normal cartridges. Gyrojets were supposed to be very accurate near-recoilless near-silent armor piercing weapons able to even work underwater like a 13mm torpedo. The system didn't see widespread use due to reliability problems (the rockets' pinhole-sized jet nozzles were small enough to easily get plugged up and not strong enough to clean themselves) and consequences of the low muzzle speed — that is, less accuracy than expected and being weaker than some slingshots at point blank range (you could allegedly prevent a round from exiting the barrel just by placing your hand over the end). Although the rockets had very low exit velocity, because they continued to accelerate they could achieve supersonic speeds - but only after 20 meters or so of acceleration. They are considered collectors' items today and can cost as much as $1,000 per round to shoot because of the rarity of the remaining ammo.
Brunswick RAW (Rifleman's Assault Weapon) — an underbarrel grenade launcher about halfway between Gyrojet and Soviet rocket-propelled grenades. Its projectile (several variants including 'flying Claymore' and HESH) is a 140mm sphere with a little tail... yes, it's a rocket clyster. Or a flying bowling ball
During the siege of Pelusium in 525 BC, the Persian general Cambyses was known for hurling live cats over the walls of the Egyptian fort to demoralize the defenders (to whom the cats were sacred). He also instructed his men to drive cats before the army, and tie cats to their shields to further deter the egyptians. He was not a nice person.
Not sure if this counts, but an early ancestor of the machine gun called a Puckle Gun (named for its inventor) fired both round ammo and special square bullets for use against non-Christians.
The U.S. Air Force once tried to make a "Gay Bomb". The idea was to load it full of sex pheromones and neutralise enemy forces by making them make love, not war.
Double A batteries make for a very dangerous projectile.
At a high school, a physics class once used leftover fetal pigs as ammo for their potato cannons. Another physics class shot squash, tennis balls, hard boiled eggs, and someone's backpack across the school playing field. The cleanup wasn't fun though...
Somewhere in the UK there is a man with a carrot cannon. He takes it to schools.
To test windows and wall material against hurricanes and tornados throwing stuff around, there is a gun which shoots lumber at them.
HESH rounds, they're essentially a slow moving round containing a plastic explosive which flattens itself against the target before exploding due to an embedded fuse, creating a shock wave that, owing to its large surface area and direct contact with the target, is conducted very effectively (and if said target is an armoured vehicle which lacks spaced armour or spall liners, it results in heavy spalling on the inside of said vehicle, cutting up the poor guys inside it) not very useful against modern tanks but is still very popular for use against bunkers and demolition work.
For an example that overlaps with Bling Bling Bang, bullets made out of white gold and tipped with diamonds. See for yourself. Unfortunately, these can not actually be fired.
The US Navy's Mk 182 Kinetic Energy-Electronically Timed round for the Mk 45 5" gun is essentially a five inch wide shotgun shell. It carries (sometimes more than) 9,000 tungsten pellets which are released when the round is detonated, putting lots of small holes in the target(s). It's meant for use against small, lightly armored boats.
And, there is always the bomb that drops more bombs, also known as a cluster bomb. There is also a cluster bomb that drops land mines, another that releases more cluster bombs, and a version that drops heat-seeking anti-tank smart bombs.
The last is the CBU-97 Sensor Fuzed Weapon (SFW). During development, it was nicknamed "The weapon of 13 consecutive miracles." It has only been used once in combat, and essentially destroyed an Iraqi armored battalion in the 2003 invasion of Iraq.
Area denial munitions. Artillery fired shells that can deploy minefields.
There are toy guns that are tiny hand-held catapults that fling little plastic figurines, like monkeys, rubber chickens, and pirates.
But this is definitely the cutest version - a Teddy Bear Gun.
During the Battle of Tora Bora in 2001, British special forces who stormed the cave complex used special frangible bullets that rather than being made out of conventional metal, were made from brittle ceramic. The idea of this was that when a stray bullet hit a cave wall it would disintegrate, rather than ricochet dangerously. It also had the added benefit of instantly fragmenting upon entering a target causing massive injury, yet still being (kind of...) legal under the Hague Convention.
Beehive rounds used to be popular for tanks that expected they would have to deal with infantry. It worked like a shotgun except that it used thin rods rather than balls. Because they were moving so fast the rods flexed in the air which caused them to slash targets like thousands of tiny knives.
Then, there's this. It's an anti-tank rocket that uses White Phosphorus instead of explosives to get the job done. It appears to rely on infiltrating through whatever chinks there are in the Nuclear-Biological-Chemical protection and causing "sympathetic detonation" of ammo.
Musketoons and blunderbusses, the flintlock predecessor of shotguns, have been known to fire anything one can shove down their large barrel.
Firearms were so named because they used to shoot fire. And pebbles.
The Chinese were fairly creative with their cannons. In addition to cannonballs and mortars, they also liked to shoot pots filled with excrement. They were called shit bombs.
Modern law-enforcement agencies use lots of different non-lethal rounds, such as rubber bullets for crowd control. SWAT teams in particular have specialized shotgun shells, such as bean bag rounds to stun without killing, and breaching rounds that will destroy a lock without sending hot lead into the room beyond.
40mm Grenade Launchers—like the M79, M203 and Mikhor MGL—can be loaded with a number of specialized ammunition. Tear-gas, buckshot, white phosphorus flare and smoke rounds are just some of the rounds available. There is even a 40mm canister shot developed for the MGL that fires a small camera with a parachute linked to a wireless device.
During WW 2, a number of strange bombs, rockets and munitions were designed for a variety of reasons with a varying degree of effectiveness. A ball-shaped bomb was developed by the British to bust dams by skipping along the water. The Americans tested bombs that delivered bats equipped with timed napalm charges. The Japanese used human-piloted rockets and torpedoes and the Germans developed cannons designed to "fire" gusts of wind to knock down bombers (Only the dam busting bomb was put into service and worked as planned). And those are the ones that got off the drawing board.
Arguably the American "Tiny Tim" rocket: A 500lb semi-armor piercing naval shell with a rocket motor strapped to it.
FRAG-12 rounds are 12-gauge miniature grenades, fired from shotguns (including the fully-automatic AA-12). They come in flavors to include fragmentation, high explosive, and armor piercing. Yes, it is as awesome as you think.
In the early battles of WW 2, the Germans devised a strange round for their standard anti-tank rifle (a rifle of sufficient calibre to fire a large projectile that would penetrate what in this period was very thin tank armour). Attached to the armour-piercing payload bullet was a small disc of solid material, which under the heat of being fired and the friction of passage through the air, would sublimate into a measured quantity of tear gas. This was intended to incapacitate the driver or crewman, should he not have been wounded by the AP round. The problem was that the round could only carry a small amount of teargas and, always assuming the gas had not been burnt off by the bullet's passage through the air, that carried by a single strike was so small as to go undetected. As this weapon was also thought to contravene Geneva Convention regulations on use of battlefield poison gas, it was very quickly withdrawn.
When Key West separated from the U.S. to form the Conch Republic, they attacked Coast Guard ships by throwing stale bread and conch fritters at them. This "battle" is reenacted each year.