Beehive catapults. Scorpion bombs. Bug pit prisons. For thousands of years, military strategists have used insects as weapons of war—not only to inflict debilitating pain on enemies, but also to deliver deadly pathogens and destroy agriculture, with the intent of causing widespread misery, sickness and hunger.

Delivering disease via insect vectors has been wickedly effective. During WWII, Japanese biological warfare units dropped plague-infected fleas and cholera-coated flies on Chinese cities—killing some 440,000 people. The Japanese military also developed plans to spread plague-carrying fleas over San Diego in 1945, but never followed through.

In 1989, domestic bioterrorists told authorities they were breeding and releasing medflies in California—and the eco-radicals would continue doing so until the government halted insecticide spraying. Had this devastating pest become established (the infestation was suppressed), the resulting quarantine on California fruits would have destroyed crops in one of America’s vital agricultural regions, costing tens of thousands of jobs and billions of dollars.

But for millennia, six-legged soldiers have been most consistently deployed to torment and disperse enemies. From Old Testament accounts (“I sent the hornet before you, which drove them out...”—Joshua 24:12) to the Vietnam War and beyond, insects have been effectively weaponized. Here are some of the most fiendish examples:

READ MORE: Sting, Recover, Repeat: How One Scientist Measured Insect-Induced Pain

At the end of the 2nd century, the Roman emperor Septimius Severus was on his way to wresting control of Mesopotamia from the local monarchs—that is, before a shower of scorpions helped waylay his plans, according to an account by ancient historian Herodian.

As the Roman legions advanced on the desert stronghold of Hatra—desirable for its control of Silk Road caravan routes—King Barsamia and his citizens holed up behind its 40-foot high perimeter walls. The defenders crafted earthenware bombshells loaded with scorpions—which were so prevalent in the region, and so dangerous, that Persian kings regularly ordered scorpion hunts and offered bounties to assure safe passage for the caravans. The locals knew first-hand that scorpions inflicted intensely painful stings and that their venom can induce irregular breathing, slowed pulse, convulsions—and occasionally death.

As Severus’s men reached the walls of Hatra, scorpion bombs rained down, inflicting agonizing punishment on the Romans wherever they had exposed skin—legs, arms and, worst of all, their faces and eyes. With arachnids deployed among the Hatreni defenses, Severus was held at bay for 20 days, until his troops finally broke off the battle and retreated.

A major breakthrough in military pain delivery came with the development of machinery capable of launching insect-heavy payloads. What the slingshot did for the humble rock, the catapult did for bees—and shifted the balance of entomological power in favor of the attacking forces.

European history is replete with accounts of beehives and wasp nests being used as warheads—including on the high seas as a highly effective way to clear the decks of an enemy ship. The technological high point in hive-heaving machinery emerged in the 14th century with the development of the entomological predecessor of the Gatling gun—a windmill-like device that propelled straw hives from the ends of the rapidly rotating arms.

But attacking forces weren’t the only ones employing stinging insects. European nobles assured that their bees were ready for producing honey or havoc, as the situation demanded. The interior walls of medieval castles were often equipped with recesses, termed bee boles, as homes for the six-legged troops.

Nasrullah Bahadur‑Khan, the 19-century Emir of Bukhara (present-day Uzbekistan), was known for his sadistic streak—and perhaps best remembered by history for what the locals called the Black Well. According to western historians, the hole was 21 feet deep, covered with an iron grate and accessible only by a rope. The Emir seeded the “Bug Pit” (as it’s known today) with insects to assure a constant, torturous experience for his victims.

The foulest of the ruler’s six-legged minions were the assassin bugs, although their eight-legged cousins, the sheep ticks, added to the torment. Assassin bugs are inch-long, carnivorous insects endowed with stout, curved beaks for piercing their prey—most often other insects. But they’ll feed on people rather than starve. The bite of these insects has been compared to being stabbed with a hot needle, and the digestive enzymes that they inject to liquefy the tissues of their prey cause festering sores in human flesh.

The Emir's jailer described how two British prisoners were slowly eaten alive as “masses of their flesh had been gnawed off their bones.” In their case, Nasrullah mercifully (in his words) ended their agony with beheading.

Using insects to inflict pain has continued into recent times. During the Vietnam War, the Viet Cong dug a network of underground tunnels allowing them to decide when and where to fight—sometimes lobbing wasp and hornet nests into U.S. positions to disrupt defenses before launching an attack.

Pity the Americans commandoes who, sent into the subterranean passages to engage the enemy, stumbled into booby traps instead. Feeling his way through a dank passage, a “tunnel rat” might overlook a trip wire and have a load of scorpions rain down from a hidden cavity in the roof.

The Viet Cong also conscripted the Asian giant honeybee, described by tropical entomologists as “the most ferocious stinging insect on earth.” Soldiers gingerly relocated colonies to trails used by the Americans and then attached a small, explosive charge. When an enemy patrol passed by, a patiently waiting VC set off the blast. The infuriated insects drove the soldiers into dangerous disarray.

For their part, the U.S. military funded a research program to devise an apparatus to spray the Vietnamese enemy with the alarm pheromone of bees, thereby converting the local insects into fierce allies. This chemical signal functions like a cavalry bugle, inciting bees to attack. But the “weapon” was never deployed. It’s a reminder that, while these insects were just doing what they’ve evolved to do—inflict pain—humans can decide whether or not to create misery And since the dawn of time, we’ve been conscripting six-legged warriors to do our brutal bidding.

Jeffrey A. Lockwood is a professor of natural sciences and humanities at the University of Wyoming and the author of Six-Legged Soldiers: Using Insects as Weapons of War and The Infested Mind: Why Humans Fear, Loathe, and Love Insects.