Monofilament Weapons
This article only describes Warhammer 40,000 weapons. For mono-filament weapons in any other sci-fi setting or game, see Monowire.
Monofilament Weapons are a type of weapon used by the Eldar and Dark Eldar. They fire a razor-sharp monofilament web, wrapping around the enemy and slicing through flesh and bone with ease. Enemies get stuck inside the webbing and try to pull themselves free, causing them to tear themselves apart. The downside of the weapon is the low speed of its projectile it has a limited range for direct combat, and has next to no armor penetrating capabilities.
Eldar
Death Spinner
The most common weapon used by the Warp Spider aspect warriors, the Death Spinner casts webs of razor-sharp material over the target, making it cut itself apart. Some Exarchs of the Warp Spiders use a modified version of this weapon, allowing them to use two of them at the same time.
Spinneret Rifle
A variation of the Death Spinner, this weapon instead fires a single strand of webbing, capable of punching through nearly anything hit. Way more effective against armor, but with a lower rate of fire than the regular Death Spinner.
Shadow Weaver
Designed for indirect fire, the Shadow Weaver casts a large web into the air which rains down on the enemy, cutting through them with as little force as the pull of gravity. It is more or less a light artillery version of the monofilament branch of weapons. Usually fielded by a few Guardians who aren't busy mounting other heavy weapons or each other.
Doom Weaver
The Doom Weaver is the Shadow Weaver on steroids: mounted on the Night Spinner Grav Tank, the Doom Weaver casts a massive web that not only cuts through entire swathes of enemies in a single shot, but remains on the ground after landing obstructing enemy movement. Anyone who tries to walk through it will find their feet suddenly shredded apart, which would probably cause them to fall on it and finding out if their face will blend. After a long enough time the web will settle into a solid blanket that can safely be walked over.
Void Spinner
Designed and fielded by the Biel-Tan Craftworld, the Void Spinner is a super heavy grav tank that uses a modified version of the Doom Weaver. The monofilament web that it sprays out is covered in superpowered bacteria and wraithbone parasites that put the Tyranid's eating habits and the Necron's killing standards to shame: Where they stop at any organic matter, these wraithbone parasites and super bacteria keep going and eat the rock and metal the planet is composed of. Of course they don't keep going till they destroy the world, they do die off after a while. The rest of the Eldar think that the Biel-Tan are monsters for creating such a machine, the Biel-Tan say that they're justified in using whatever they need to reclaim their empire.
Dark Eldar
Shredder
Employed by the Dark Eldar, the Shredder fires a burst of of barbed monofilament designed to shred and maim all targets in a small area.