Cows
The trebuchet was arguably the atom bomb of the Middle Ages — a game-changing siege engine that could catapult projectiles over unprecedented distances and heights. The machines lobbed giant stones, flaming barrels of pitch and even the decapitated heads of enemies. Most noxious, though, was the widespread tactic of launching the rotting, diseased carcasses of livestock, mostly cows, over the walls of citadels and cities under siege — a form of medieval biological warfare. Having to weather slings and arrows would have been tricky enough; imagine coping with pestilential stink bombs flying into your midst. During a 1340 siege of a fortress in northeastern France, the defenders wilted amid a bombardment of animal parts: "the stink and the air were so abominable ... they could not long endure," wrote one chronicler.