Fictional weapons are inverse lethal: The more effective they should be, the less they are. That's why a henchman holding a machine gun is just telling Daredevil where to punch, but Jackie Chan holding a priceless Ming vase is functionally immortal. And when a weapon gets powerful enough to threaten the entire planet, it reverses the polarity of even having a weapon by killing its own evil genius instead.
But like most laws, both physical and legal, this gets ignored when a good guy meets a monster, which is why good guys have gotten away with using weapons more suicidal than a noose made of razor wire. Here are eight fictional weapons that would work only against life insurance claim investigators, because they make your suicide too stupid and confusing to prove.
The Lancer is the Ashley J. Williams of automatic weapons: a gun, a chainsaw, and all the ass-kicking you could ever need. The justification for building a chainsaw into a gun was obviously someone having the idea at a game design meeting, followed by high-fives so intense that they were felt on the International Space Station. The first time I got a chainsaw "kill," I felt like I'd just discovered and lost a new kind of virginity.
In the real world I still have armpit virginity, and I am entirely OK with that.
It comes from Sera, an insane fictional world of violence where owning an assault rifle isn't already crazy enough. That might be because the average Seranian looks like a linebacker played at the wrong monitor resolution. Their belt sizes are measured in giant redwoods. It takes slightly longer to shoot one to death than to teach them the theory of relativity.
Gears of War gunfights can take longer than postal chess.
The monsters on Sera are Locusts, and their hides are so thick that bayonets get stuck in them. So Gears of War replaced the bayonet with a series of smaller blades and fitted them to a motor. The first time you try to chainsaw a Locust, the small blades will dig into its flesh and the motor will fling the Lancer out of your hands and over its shoulder, giving the attacking monster's backup a free Lancer. Your only hope is that they spend so long desperately trying to get a chainsaw kill that you can blast them with the shotgun, just like everyone else on multiplayer.
The first Dragonlance trilogy was My First Fantasy Novel for millions of fans (and also the authors). It reads like fan fiction of a Dungeon & Dragons party because that's exactly what it was. The books contain more elementary fantasy stereotypes than the first D&D players manual. And I loved them. Read them twice. Raistlin could kick the shit out of Gandalf with both hands behind his back and a squeegee mop instead of a staff.
Clyde Caldwell, TSR Inc
Raistlin: more magic than a flashlight and a bird call. Unlike some wizards.
In Dragonlance, the world is under attack by ancient master-magician dragons that breathe lightning and poison and can bite through an elephant. The only way mortals can stand against them (and you know you've got problems when "mortal" is the adjective you're bringing to the fight) is with the Dragonlance. A pointy bit of metal. You're going up against near-gods and your best idea is to joust at them. When your battle plan is based on approximating the murderous incarnation of mythical evil as a balloon, you're in trouble.
"OK, men, get as close to the impossible death beast as possible, then start poking it."
You also need a good dragon to carry you up there. This means going up to a good dragon, the most ancient and powerful creature in existence, and explaining that you're going to ride it like a horsey while murdering its kind. Good luck with that.
Krull achieves the double-impossible by:
a) having a flying Force-powered magical buzzsaw
b) making it boring
But that's because Krull happens when someone tries to create an epic fantasy hero, puts on a pair of tight leather pants, and has run out of ideas. The magical weapon was a glaive designed by someone who didn't understand the words "glaive," "weapon," or "amputation is bad."
"Call for a healer, it's just slashed my wrist."
The blades flick out of each arm. The only enemy this could work against is a kleptomaniac Hecatonchires. Throwing it would actually work, because flinging your own fingers at someone usually freaks them out too much to punch you. Or if you're under attack by yakuza, you've just profusely apologized. This has to be a plot by the movie's bad guy. If I was spreading rumors about a magic weapon that was the only thing that could kill me, this is what I'd choose, too.
"No, seriously, that's my only weakness. Don't try bullets."
Even the weapon is so embarrassed that, despite being covered in penknives, it flies by itself and vaporizes anyone it kills. It doesn't even want forensic archaeologists working out how stupid it must have been. With a self-guided everything eliminator, the fantasy world's first drone, you might wonder why the good guy doesn't just throw it and stand back. Prince Colwyn wonders that for a full five minutes in the big fight against The Beast*. Where most fantasy movies climax with a desperate struggle, all exciting strikes and counter-thrusts, Krull's climax has the hero looking like he can't reach his heart medication.
*Told you the writer had run out of ideas.
"MUST ... GET ... OUT OF TERRIBLE MOVIE!"
That indistinct smear behind the ruins is the closest the monster gets for the entire fight.
Even if you can work the stupid thing, you'll die of boredom. And boredom combined with too many knives is how we ended up with emo.
ROCKET SLEDGEHAMMER! Bollocks to words, behold this glory.
A regular sledgehammer is how you tell people committing assault with blunt objects that you think they're a bit fancy. The Rocket Sledgehammer is how you apply for the position of Thor and remove an entire dimension from anyone who objects. It's what happens when Mjolnir is cast down to Earth and hits a Saturn V that was on the way up: the most awesome explosion in history, then both science and myth wipe the blood off their lips, gaze at each other with newfound respect, and proceed to passionate lovemaking, giving birth to the ultimate in badass weaponry.
A weapon that would make Grabthar piss himself.
This weapon makes the Lancer look like manicure equipment. You're putting the law of conservation of momentum in an armbar and hitting people with it. It doesn't matter what monster you're fighting: it's doomed, and that's all the CSI team will be able to tell about it afterward.
But the more awesome the weapon, the more unusable it is, and the Rocket Sledgehammer is more overkill than throwing a Big Bang grenade to clear an enemy trench. Activate the rocket and it'll rip your entire arm out of its socket, then blast off to make sure it can't be found in time to be reattached. Firing this will extremely literally disarm you.