A 'mangonel was a type of catapult or siege machine use in the medieval period to throw projectiles at a castle's walls. The mangonel had poorer accuracy than a trebuchet (which was introduced later, shortly before the discovery and widespread usage of gunpowder). The mangonel threw projectiles on a lower trajectory and at a higher velocity than the trebuchet with the intention of destroying walls, rather than hurling projectiles over them. It was more suited to field battles. Mangonels shot heavy projectiles from a bowl-shaped bucket at the end of the arm. The bucket could launch more rocks than a sling; this made it different from an onager. In combat, mangonels hurled rocks, burning objects (fire pots, vessels filled with flammable materials that created a fireball on impact), or anything else readily available to the attacking and defending forces. The more unusual types of projectile included dead, and often partially decomposed, carcasses of animals or people, used to intimidate, demoralize, and spread disease among the besieged. This tactic often proved effective. The short supply of food, which was often of low quality or rotting, combined with the cramped living space of the defenders, poor hygiene, and vermin infestations provided an ideal scenario for the spread of disease. It should be noted, however, that the mangonel's principal role in battle, particularly medieval battle, was to knock down a castle or city's walls and infrastructure, not to kill/demoralize troops. Its unpredictable, yet powerful strikes were best suited to hitting broad, non-moving targets such as buildings or walls. Mangonels might also have thrown burning sand at enemies, the hot sand would enter openings in armor, leading to painful burning or death.