Blowgun

Out of all of the ranged weapons humans made during the earliest days of man, very few are as exotic as the blowgun. The blowgun (also called a blowpipe or blow tube) basically consist of a narrow and hollowed out cylinder, usually made out of wood. The user adds some light projectile ammo of their choosing, usually darts, but it can be many things, from little stones to iron pellets designed to do more damage. Once the ammo is introduced, the user then blows the gun to fire the weapon.

History and uses

The idea of the blowgun probably came from someone just blowing hollowed tree trunks, and as such, it is one of the most ancient ranged weapons ever created, possibly older than the bow. However, the weapon has a problem, which is its inability of dealing massive damage to big targets: even though one can increase the weapon's strength and accuracy by making the blowgun larger, because it uses the strength of the human lungs, it can only reach some strength. It also limits itself to small ammo, due to the weapon's size. Like the axe and the bow, the blowgun was used mainly as a hunting tool, very useful against fast and small targets like birds, rodents and monkeys, and then they realized it could work just as well against people. To further improve the weapon, many cultures designed different types of darts, usually consisting of an small and elongated body with a needle at the end, and further improved by adding different kinds of poisonous substances. The most famous cases of this are the use of the "poison dart frogs" (take a guess why they're called that) and the plant extract called curare by many native south-american tribes, both of which induce rapid paralysis and death by asphyxiation. But really, any toxin that kills quickly will work. If you don't care about that, you can use anything, from corrupted water to shit, and that will cause the target to get incredibly sick and die if they don't get the adequate treatment. It can also be used with more stern and solid materials, to try and use the concussive force of the projectile, but the size of the weapon usually means they have to be aimed at very specific points, such as the eyes, head temple or the neck.

This weapon has been widely used throughout History, due to its easiness to use and to craft. However, it was quickly displaced with the arrival of weapons such as the bow, the slingshot and firearms. It continued to be used as a weapon of war by tribal societies, specially in combination with different poisons. More advanced societies kept using it, though, but normally in more secretive context, like assassinations. Modern versions are either civilian/hunting equipment, compressed air guns for recreational use (like airsoft, BB, paint, or gel-ball games), or spy tools with nasty poisons.

Use in fantasy settings

The blowgun is very common in fantasy settings, specially those that draw inspiration from Pre-Columbian societies (and mesoamerican civilizations in particular) or South-East Asian tribal societies.

In D&D and Pathfinder they are among the worst of all possible weapons to try and use. They deal almost no damage, require high-end weapon proficiencies, and have inferior range and fire rate compared to bows.

The Pygmies of Warhammer Fantasy used blowouts as a common weapon.

For modern settings, anything that involves spies (usually in WW2, but especially during the Cold War) typically includes some weapon that can be categorized as a blowgun on the merit of the main propellant being pressurized air in the form of an air gun. If you're watched some James Bond movies or read a spy thriller, chances are high, something in this direction was used.

Medieval Weaponry
Melee Weapons:	Battleaxe - Dagger - Lance - Mace - Club Pole-arm - Spear - Sword - Warhammer
Ranged Weapons:	Blowgun - Bows and Arrows - Cannon Crossbow - Firearm - Rocket - Shuriken - Sling - Incendiary Weapons - Artillery
Armor:	Armor - Fantasy Armor - Helmet - Pauldron - Shield