Is there some piece of machinery so important to your everyday life that you'd hack off a limb to have it at all times? Tons of science fiction characters have made that choice or had it made for them. Most go for the classics, like strong robotic prosthetics or massive hidden guns, but some chrome is one of a kind.
Powerful robot limbs seem to be fairly attainable with modern technology. We may be only a few years away from elective cybernetic surgery. Sci-fi creators have had decades to imagine all the crazy stuff we'd want to put into our bodies, but some augmentations score bonus points for creativity.
Doctor Octopus' Mechanical Arms - Spider-Man 2
Sam Raimi's take on Dr. Otto Octavius took most of its inspiration from the comic books, with one massive deviation. Like in the comics, Octavius built a set of four metallic limbs that could handle materials too dangerous for his human limbs. A laboratory disaster results in those arms being permanently grafted to his body. However, instead of a form-fitting harness, Alfred Molina's robot arms are attached to his spinal cord. In addition, they aren't just additional limbs. They're artificially intelligent machines with minds of their own. This version of Doc Ock is one of the most compelling in the history of the character. His additional cybernetic limbs are beautifully realized and engaging to watch, but the added element of a functioning rogue AI makes them fascinating.
Grewishka's Grind-Cutters - Alita: Battle Angel
Robert Rodriguez's adaptation of Yukito Kishiro's beloved cyberpunk manga series featured a ton of excellent action sequences. Christoph Waltz's rocket hammer, Alita's roller derby battle royale, sword fights between multiple cyborg killers, and much more. Though he gets lost in the shuffle, Jackie Earle Haley's muscle-bound henchman Gewishka is fitted with a great weapon. In his first appearance, he's only armed with his massive body. However, after being easily destroyed by Alita, he replaces his arm with a series of grind-cutters. These shiny chrome murder weapons are like Ivy's snake sword from Soul Calibur affixed to each finger. They're a lethal melee weapon and an effective projectile weapon that makes for some spectacular action setpieces. Their most notable moment comes when Alita dives through a flurry of spinning blades. If these blades were in the hand of a more competent warrior, they'd be unstoppable.
Gigan - Godzilla vs. Gigan
This tragically ignored member of Godzilla's giant monster entourage sports a laser eye, a pair of steel hooks for hands, and a massive rotating buzzsaw in his chest. Gigan was once a normal massive reptile, not much different from any other kaiju, but he was trapped by a race of aliens called Nebulans who forced cybernetic enhancement onto him. Over his few film appearances, Gigan demonstrated a built-in jetpack and grappling hooks in his arms. His final depiction, in Godzilla: Final Wars, gave him saw blades that fired from his neck, and a bladed tail, and eventually replaced his hooks with chainsaws. Gigan is a Mr. Potato Head of death, constantly swapping out murder weapons for fun. He introduced cybernetics to the world of Godzilla movies and his seemingly random selection of augmentations is consistently entertaining.
Briareos Hecatonchires - Appleseed Alpha
Though Masamune Shirow is much better known for his other cyberpunk manga empire Ghost in the Shell, Appleseed is an underrated entry in the subgenre. The story follows two E.S.W.A.T. (Extra-Special Weapons and Advanced Tactics) members keeping the peace in post-World War III Los Angeles. Briareos, the secondary main character, is 75% cybernetic. His body was damaged, and his identity was lost in the aforementioned war, leaving him in a mixture of real and artificial skin. He has the traditional improvements to strength, speed, and skill, but his more in-depth tech is much more interesting. His surname Hecatonchires actually refers to the model of his cybernetic body and the power it gives him. Briareos can control multiple additional limbs and occasionally several bodies independently of each other. This allows him to fight as a one-man army. His most noticeable augmentation is his head, which is outfitted with eight eyes for panoptic vision, a robotic auxiliary brain, and a pair of rabbit ears that allow him to express emotions. He's a complex machine, and among the best-case scenarios for World War III casualties.
Monomolecular Filament - Johnny Mnemonic
Ever wonder where Cyberpunk: 2077, or the tabletop game that inspired it got the idea of a very thin wire as a built-in weapon? As with so many other cyberpunk ideas, it came from William Gibson. Gibson's 1981 short story "Johnny Mnemonic" and the slightly underrated 1995 film adaptation introduced Shinji, a textbook cyborg ninja assassin. He's unassuming, he blends in easily, and he's not visibly armed. However, his left thumb is artificial. It snaps off just above the first joint, revealing a spool of extraordinarily strong wire that can slice through matter on a microscopic level. The thumb acts as a counterweight, allowing the weapon to function as a garrote, whip, or flail. This concept has been repeated in countless other cyberpunk works, but give Shinji the credit he deserves for starting the trend.