A weapon that shoots a single spike forward, which then retracts so it can be fired again, just like a pile driver.
A common weapon in the Real Robot Genre and other Sci-Fi works, but not necessarily used by the the mecha themselves, as there are sometimes hand-held variants. Also, oddly, a uniquely Japanese trope, with very few non-Animesque Western examples. They work much like Real Life pile drivers, but rather than operating continuously (for example, hydraulically), they typically work with a one-shot chemical charge that drives the metal stake or penetrating spike, complete with Spent Shells Shower and a revolver mechanism.
The spike usually returns to its original position after each "shot" (though how is not always apparent). Also, the pile bunker's firing mechanism must be made from incredibly strong materials, or it will explode every time the spike strikes the target, similar to gun with a jammed barrel. Alternatively, it won't be able to penetrate a tough enough target. Also note that it would need to include a stopper made from equally strong materials that prevents the spike from simply flying out of the barrel like a bullet, thus having much greater attack range, which begs the question of why the spike, in fact, isn't simply fired like a bullet (although it could potentially be justified if the spike has to be made from specific, very expensive materials, such as that making multiple bullets out of them would be unaffordable, or if it is too heavy to carry additional spikes).
Guns that fire the spike away should go into the nailgun category.
- Cyan Pile uses one in Accel World.
- Featured prominently in Armored Trooper VOTOMS and its spinoff, Armor Hunter Mellowlink. The hero of the latter especially likes to finish off his oponents with the pile bunker attachment on his AT-rifle. Armored Troopers, on the other hand, work on the principles of this trope via punching with the arm, as they spend rounds to quick-fire a punch, without a stake or spike present.
- Dai-Guard's Knot Buster and Knot Punisher. Justified, since they have to be very precise, easy to use and very powerful to accurately destroy Fractal Knots.
- Mobile Suit Gundam F91 introduced a weapon called the Shot Lancer which effectively combines the Pile Bunker with the Jousting Lance; its main goal is to let pilots disable enemy mobile suits without triggering a catastrophic reactor explosion (which is extra bad when you're in a space colony). The Shot Lancer also turns up in the sequels Crossbone Gundam and V Gundam
- In Mobile Suit Gundam: Iron-Blooded Orphans: the mace wielded by Gundam Barbatos is equipped with a Pile Bunker that fires from it's tip. The Graze Ein also has a pair of these mounted on each arm. Ein uses one of them to critically injure Shino, and another one for breaking the Barbatos Wrench Mace. Unlike most examples, they are single use and once fired, they detach themselves instead of retracting.
- Charlotte Dunois' Rafale Revive Custom II from Infinite Stratos can carry a pile bunker weapon module hidden in its left shield.
- In Neon Genesis Evangelion, Sachiel, the very first Angel encountered, has one in its palms (when retracted, the spikes extend from the Angel's elbows). It pierces right through the protagonist's mecha's eye, in a very painful-looking way.
- In Bleach, Gin primarily uses his Zanpakuto (an extending sword) like a pile bunker.
- In Gamaran, Banri Omiya wields a special "kuda yari" (tube spear) and, thanks to the above-mentioned tube, can use it to stab, withdraw and stab again at a very fast speed, like a pile driver indeed.
- The Big O has these as one of its signature weapons. Each of its massive arms contains a piston which is used to amplify its punches.
- Ginkotsu from the Band of Seven is shown to have one built in his chest, but is destroyed before he can use it on Inu Yasha.
- In Senki Zesshou Symphogear Hibiki Tachibana is unable to make her Gear summon weapons, so instead she learns to convert its wrist and calf armor into piston-like structures which can be "fired" to add more force to her punches and jumps. By the second season she has upgraded to rocket-propelled pile bunkers, and can use them as a delivery system for the team's Combined Energy Attack.
- Crusadermon has one of these built into his/her arm, though it shoots magical blasts instead of stakes.
- The movie adaptation of Magical Girl Lyrical Nanoha A's gives Reinforce a parasitic pile bunker as a physical representation of her corrupted Defense Program. According to supplemental material it's an Ancient Belkan Anti-Armor weapon modified from a wrist-mounted spear thrower.
- Ikoma has one as a Weapon of Choice against the Kabane from Kabaneri of the Iron Fortress.
- In Hiroshi Sakurazaka's All You Need is Kill, the Jackets used by the Japanese troops carry one of these with a clip of twenty charges. They're only marginally effective, but still one of the best options they have.
When they first told me its magazine only held twenty rounds, I didn't think anyone could live long enough to use even that many. I was wrong. Mine had four rounds left. I had missed fifteen times—maybe sixteen.
- In No Country for Old Men, both the book and the film, Anton Chigurh wields a captive-bolt pistol which is a Real Life version of this used for dispatching cattle humanely.
- The M.S.G Weapon Unit MW28 Impact Edge is a pair of spring-loaded Pile Bunkers, and the magazine at the top acts as the trigger for them. It received a re-release which is included in the Frame Arms Girls Architect kit.
- Anarchy Reigns: Douglas Williamsburg has two, built into both arms.
- The Alt Eisen◊ of Super Robot Wars has a Revolving Stake mounted on the right arm. The machine's Mid-Season Upgrade (the Alt Eisen Riese◊) and variants all carry the same weapon.
- Similar Original Generation weapons include Rapiecage's Magnum Beak, the equipable weapon "G-Impact Stake", the claws wielded by the Strike Guarlion in the Record of ATX manga, and Cerberus Ignite's "Ignite Pike". Additionally, Haken Browning from Endless Frontier wields the Night Fowl assault rifle with an underslung stake below the barrel of the weapon.
- Bloodborne has one in the form of the Stake Driver, a weapon that can be used with the spear-like blade either extended or retracted, and causes a detonation at the tip if an attack is fully charged with the blade retracted.
- Earth Defense Force 2025 / Earth Defense Force 4 in Japan: The Fencer Power Armor character has a variety of pile bunker like weapons available to them some causing additional effects like explosions inside the target from forcefully injected plasma. Earth Defense Force 5 also sees the Fencer equipped with pile bunker-like weapons, such as the Blasthole Spear.
- Those in Front Mission look very much like some Armored Trooper VOTOMS versions.
- One of Barret's Arm Cannon attachments in Final Fantasy VII.
- Lost Planet has them as a hand-held weapon, and one for the mecha.
- Armored Core has them, too.
- Also by From Software, the now forgotten Xbox 360 game Chromehounds featured several versions of these, but powered by hydraulics, not explosives.
- Dig Dug's Taizo Hori wields a giant Pile Bunker in Namco × Capcom.
- R-Type Final has several ships with a pile bunker in place of a charged laser weapon. The bunkers do absolutely immense damage, in some cases more than enough to One-Hit Kill a boss... but they're extremely short-ranged and getting close enough to use them without killing yourself is very difficult.
- Metal Slug 5 has it as the Slug Gunner's melee weapon, although this one can't really shoot over a distance.
- In Metal Slug 3D one of the weapons that can be fitted to the customizeable Slug is a Pile Bunker that can be shot out on a chain or used as a ramming tool. Another part having a similar function is Gunner Arm, essentially two Pile Bunkers placed onto the vulcan parts, if one equipped all Gunner Parts, the Slug will transform into Slug Gunner.
- Ragnarok Online has a weapon by that name, but with no special qualities other than its incredible power (and weight), and a skill that truly goes with the trope - it's an attack used by Mechanic class while in their Madogear and it has a good chance to cancel any defensive spells or skills on the target it strikes. Only downside of the skill is that you need to equip the no special qualities weapon mentioned above.
- Steel Battalion: Line of Contact introduces the Garpike, a VT whose signature weapon is the pair of Bang Needles flanking its sides, which punch through their target and explode.
- An unlockable weapon in The 3rd Birthday.
- Aigis acquires one in Persona 4: Arena which she uses to start off her All-Out Attack.
- While he doesn't use one himself, Slayer from Guilty Gear has this as the name for one of his special moves, which is a sliding straight Megaton Punch (that supposedly punches with the force of an actual pile bunker).
- Chuck has one as his weapon in Wild ARMs 5, making him one of the 3 melee characters.
- Many of the walker-type robot characters in Tobal 2 use this as their melee attack.
- Zenia Valov from Arcana Heart has one in her Power Fist named "Edinorog". That's Russian for "unicorn".
- The Power Fist in Fallout 4 can be modified like this. The Puncturing Power Fist upgrade straps a block of concrete with pieces of steel rebar sticking out to the power fist's impact plate. This increases the fist's damage and gives it armor bypassing capability.
- Monster Hunter has the Dragonators, which are building-sized pile bunkers powered by steam and used to spike monsters that are large enough to be targeted.
- The Scale, the fourth boss of Furi, wields a pair of pile bunkers.
- This is the strongest but slowest melee weapon option in Rogha Armor Force. It had the most limited targeting arc (mostly consisting of attacking directly ahead in a single linear direction) and takes the most time to recharge between attacks, but makes up for it by destroying any non-miniboss enemy with a giant steel spike through the face.
- S.L.A.I.: Steel Lancer Arena International features the Carro's 'pile hammer' melee weapon. As might be expected, it is a slower but more powerful close range weapon that attacks directly ahead of the Carro in a straight line. The problem is that SLAI is a third-person high-speed arena-combat mech-sim, and thus the pile hammer is not nearly as effective a melee weapon as other manufacturer's offerings.
- Mega Man 11 has the Robot Master Impact Man, who uses this as his weapons of choice. Mega Man acquires the Pile Driver after beating him which combines this with Dash Attack.
- Most versions of Rumble from Transformers have a pair of these for arms, except blunt. He uses these to create small-scale earthquakes. Oh by the way, Rumble is a Cassette-bot that fits into Soundwave's chest.
- Armodrillo from Ben 10: Ultimate Alien has pike-bunker arms that are likewise blunt and used to shake the earth.
- In Steven Universe, Bismuth, the blacksmith of the Crystal Gems, created a weapon called the "Breaking Point" that was specifically designed to shatter a Gem's gemstone in a single strike, destroying them.
- Captive-bolt humane killers, used by abattoir workers or vets in some areas as an alternative to the bolt-gun type, operate on much the same principle.