The Jiki Jiki no Mi enables the user to generate magnetic fields that can either attract or repel metallic objects to and from their body as they please. This makes them particularly effective against the majority of weapons in the world: namely swords, guns, and cannons. By using repulsion, the user can deflect metal projectiles back to where they came from, turning them against the aggressor. Using attraction, the user can strip opponents of their weapons and bring them to their own body, rendering said opponents helpless. The user can also use attraction to pull themselves to large metal objects like ships, allowing them to travel through the air in a manner resembling flight. In general, the magnetic forces creatable are extremely strong and very difficult, if not impossible, to resist; by wrapping a metallic arm around Big Mom and repelling it, Kid was instantly able to send her flying up in the air, a noteworthy feat considering Big Mom's massive size and weight.
The fruit gives the user a sufficient degree of control over their magnetism to accumulate a large amount of metallic objects around their body and form them into specific shapes; the user can then move these masses around very fluidly. This has been seen repeatedly with Kid, who has accumulated metal objects on his body to form normally-functioning apparatuses like mechanical arms, Gatling guns, and even exoskeletal fighting machines. Provided there is enough metal around, the users' creations can become very large in size quite easily and are, thus, capable of inflicting tremendous damage with simple attacks. Even with massive apparatuses attached to his body, Kid has never shown himself to be physically burdened by them. Objects assembled with magnetism can maintain their structural integrity even after being separated from the user's body. Since the majority of these creations consist of random pieces of scrap metal held together purely by magnetism, attacks that damage these creations typically do little against the user, as they can just reform them with ease.
As with other Devil Fruits, this fruit's ability is capable of being awakened. When awakened, the user is capable of turning other objects, including living organisms, into magnets. Should the user's target be affected by this with a significant amount of metal surrounding them, they will be quickly crushed by the metal, with the forces of attraction being strong enough to even rip large, established structures toward them.
However, in order to form these creations, the user must have a sufficient amount of metal around them. During the raid on Onigashima, Kid was forced to run around the island for quite some time in order to accumulate enough metal pieces to utilize in the impending confrontation with Kaidou and Big Mom. The fruit appears to have no effect on Pacifista despite their metallic composition. One possible explanation for this is that the magnetism exhibited by the Devil Fruit is only capable of affecting ferromagnetic metals, such as iron, cobalt, and nickel (including their alloys, such as steel, and the 'magnets' created by the awakened ability). Otherwise, the user is affected by the standard Devil Fruit weaknesses.
Kid makes heavy use of both attraction and repulsion during combat. Through repulsion, Kid repels metallic objects away from himself as a counter-offensive measure, such as reflecting a cannonball back towards its shooter. Through attraction, Kid draws in various metallic objects (often disarming his enemies in the process) and then assembles a mechanical contraption made from said objects. By far, Kid's most common application of the latter ability is to form gigantic, metallic arms connected to his actual ones, employing those in close-ranged combat.
Kid can shape random metallic objects into fully functional limbs, tools and weapons in a short amount of time and with no apparent difficulty, demonstrating a high degree of mastery over his Devil Fruit ability coupled with excellent engineering skills. Despite being dismembered by one of the Four Emperors, Kid easily adapted to his lost arm by successfully replacing it with a makeshift prosthetic arm created from his magnetic powers. In the event that Kid loses his prosthetic arm for whatever reason, he can just make another one on the spot with any metal items he manages to attract to himself.
Kid has mastered the fruit's ability to the point of awakening it. However, he is not used to his awakening yet and only uses it as a last resort due to the large amount of stamina it draws from him.
Repel (反発,Riperu?, literally meaning "Repulsion"): Kid holds out his open-palmed hand in front of a metal object approaching him and repels it back in the direction it came from. Kid can also repel a person if he covers a portion of their body in metal (which can include even his own prosthestic arm) beforehand, letting the repelled metal covering push them away. This attack was first seen at the Human Auction House where he repelled a Marine cannonball at high speed back toward the shooters.
Punk Gibson (磁気弦,Panku Gibuson?, literally meaning "Magnetic String"): Kid attracts metal pieces to one of his arms in order to form a massive, makeshift arm. He then slams it into his opponent, crushing them. Kid first demonstrated his attack on Sabaody Archipelago, when fighting the Marines outside the Human Auctioning House. It only received a name during the Wano Country Arc after he used it on Scratchmen Apoo at Onigashima. Its name may be inspired by Gibson, a US manufacturer of guitars.
Punk Rotten (磁気魔人,Panku Rotton?, literally meaning "Magnetic Demon"): Kid attracts a large quantity of metal from his surroundings and shapes it in the form of a gigantic skull-faced demon-like golem made of scrap. The demon is composed of a floating torso with two disembodied arms, with Kid seating himself on its back and controlling it from there. Because it is made of random pieces of scrap metal, the demon can break down and be rebuilt as many times as Kid wants with his magnetic abilities, without major consequences to him. This attack was first used to destroy a ship of the Beasts Pirates in conjunction with Monkey D. Luffy and Trafalgar D. Water Law, although it was kept unseen at the time. Punk Rotten only truly debuted during the rooftop fight against Kaidou and Big Mom. The name of the technique may be inspired by Johnny Rotten, lead singer of the late-1970s British punk rock band Sex Pistols.
Punk Vise (磁気万力,Panku Vaisu?, literally meaning "Magnetic Vise"): After forming Punk Rotten, Kid makes the golem crush a target with both hands. This attack was first seen in use against Kaidou. Since both "Vise" and "Vice" are rendered the same in katakana (ヴァイス,katakana?), the technique's name may be inspired by the British punk rock band Vice Squad.
Slam Gibson (破壊弦,Suramu Gibuson?, literally meaning "Destruction String"): Kid uses his golem's arms to grab his opponent and slam them to the ground. It was first used against Kaidou. As deducted from the name, this move may be a reference to guitar smashing, a common practice for rock musicians on-stage.
Punk Pistols (磁気ピストルズ,Panku Pisutoruzu?, literally meaning "Magnetic Pistols"): Kid forms a giant harpoon gun out of metal pieces around his right arm, from which he is capable of rapidly firing metal spears at a target akin to a Gatling gun. It was first used against Big Mom, but the move failed since the spears could not pierce through her incredibly tough skin. Its name may be inspired by the British punk rock band Sex Pistols.
Assign (付与,Asain?, literally meaning "Granting/Bestowal/Assignment"): Kid touches a foreign object or person and thereby turns them highly magnetic. First used against Big Mom, the technique caused Napoleon to be stuck to her head.
Punk Clash (磁気激突,Panku Kurasshu?, literally meaning "Magnetic Clash"): After magnetizing someone else with Assign, Kid greatly increases their level of attraction, causing them to draw countless pieces of metal from large distances towards them. When used against Big Mom, she was quickly buried underneath a mountain of steel beams that were part of the framework of Kaido's Castle. The name of this technique may be inspired by the British punk rock band The Clash.
Video Game-Only Techniques
Genocide Raid (ジェノサイド・レイド,Jenosaido Reido?): A technique in the video game One Piece: Gigant Battle! 2 New World, Kid creates a vortex of metal pieces around the enemies that seem to both shock and pummel them at the same time, knocking them off their feet.
When using his Devil Fruit ability, purple electrical sparks emit from Kid's hands, so his ability may resemble an electromagnet.