In early 1942, a dental surgeon from Pennsylvania named Dr. Lytle S. Adams sent a letter to the White House with an idea for a weapon that he believed would wreak havoc on Japan. Inspired by a trip to Carlsbad Caverns in New Mexico, Adams’s proposal was to attach incendiary devices to bats and drop the winged weapons from airplanes.

Of the thousands of unsolicited civilian suggestions mailed to Franklin D. Roosevelt, somehow this one got the green light and was handed over to the Army Chemical Warfare Service. The idea behind the “bat bombs” was that bats armed with timed incendiary devices would be released over a Japanese city. They would naturally scatter in all directions, settling in the eaves of homes of businesses, where they would trigger a massive firestorm.

“It kind of makes sense!” says Curatola. “Bats like to live in eaves. They like it where it’s dark. You can put these little timers on them. It might have actually worked had they used it.”

Both the U.S. Army and Navy spent millions of dollars and captured thousands of bats in multiple attempts to make this batty idea work. The project was finally canceled in 1944. Adams swore that bat bombs would have been more destructive than the atom bombs dropped on Hiroshima and Nagasaki, but would have caused fewer civilian deaths.

In 1943, the U.S. Air Force joined Great Britain in its strategic bombing of German cities, targeting factories, warehouses and transportation hubs. As the ruthless bombing campaign continued, the German military faced a crippling shortage of conventional weapons compared with the Allies, who were churning out airplanes and tanks at a record pace.

In response, Adolf Hitler and his Propaganda Minister Joseph Goebbels announced the construction of Wunderwaffen (“wonder weapons”)—advanced weapons that would strike fear into the Allied enemy. Chief among them were Germany’s massive V-1 and V-2 rockets launched from locations in continental Europe to hit targets in London.

“What you’re seeing here is the creation of new and unusual weapons while Germany is running out of resources—aluminum, steel and other metals—and they’re also running out of pilots,” says Curatola. “Many of these weapons are what they come up with out of desperation.”

Some of Germany’s “wonder weapons” were far from wonderful in practice. A prime example was the Windkanone (“wind cannon”), an anti-aircraft weapon that didn’t fire a projectile. Instead, it shot a blast of air (compressed nitrogen and hydrogen) with the aim of knocking enemy aircraft out of the sky.

In tests, the wind cannon could snap a wooden board in half from 200 meters (656 feet) away. But in its single deployment on a bridge over the Elbe, Hitler’s expensive air gun was a dud.

In the early years of World War II, German U-boats terrorized the North Atlantic, sinking British Navy vessels and civilian ships. The most vulnerable zone was the “Mid-Atlantic gap”—a stretch of sea too far from American or British shores to be patrolled by U-boat-spotting aircraft.

One idea was to park a massive aircraft carrier in the Mid-Atlantic gap that could serve as a refueling and launch site for Allied patrol planes. With steel and other resources in short supply, one British inventor pitched a creative solution. Why not build the floating air base out of ice?

With the help of a molecular biologist, George Pyke invented “pykrete,” a bullet-proof material made from ice and wood pulp. Pyke drew up plans for “Project Habakkuk,” a floating fortress a mile long and weighing 2.2 million tons. Its hull was thick enough to repel torpedoes and a hollow interior could store planes and smaller ships. Even better, any damages could be quickly repaired with more ice.

A 1,000-ton scale model was built and tested on a lake in Alberta, Canada. But by the time the design was finalized, long-range fuel tanks on patrol planes made the ice-cube carrier obsolete.

“Warfare accelerates innovation in ways that wouldn’t have happened in peacetime,” says Curatola. “We can snicker at them now, but that’s what innovation is all about.”

The spy gadgets created by the top-secret British Special Operations Executive (SOE) during World War II provided real-life inspiration for the fictional James Bond. The SOE hid explosives inside every disguise imaginable, including Chianti bottles, Balinese wood carvings and even dead rats.

SOE agents in London procured 100 dead rats under the pretense of a lab experiment. They stuffed the rats with plastic explosives and shipped them off to agents in German-occupied France, who were supposed to plant the dead rats near the boilers of factories and trains. The idea was that unsuspecting German soldiers would pick up the dead rats and chuck them into the boilers, triggering huge explosions.

“That’s assuming that someone scoops up the rat and throws it into the boiler,” says Curatola. “There’s a step missing between step 1 and step 3. How do you ensure that the rat gets into the boiler?”

We’ll never know. The Nazis intercepted the package of dead rats and sent specimens to German military schools advising cadets to be on the lookout for exploding rodents. In an SOE report, the agency concluded that the failed mission had an “extraordinary moral effect” on the Germans, spreading widespread paranoia of “rat bombs” that didn’t really exist.

The D-Day Invasion of June 6, 1944, was years in the making. While the Allies formulated their plans for “Operation Overlord”—a full-scale amphibious invasion of Normandy, France—the Germans constructed hundreds of miles of fortified artillery positions, minefields and trenches known as the “Atlantic Wall.”

The Allies needed to invent new weaponry and new technology to breach the Atlantic Wall and push inland into Normandy. Some of these creative solutions were hugely successful, notably a group of tricked-out tanks called “Funnies.” Some Funnies had rotating flails that safely detonated landmines and others could breach an anti-tank trench by deploying a bundle of logs as a bridge.

But not every D-Day device fared so well. Enter the “Panjandrum,” a rocket-propelled metal wheel armed with explosives. The unmanned Panjandrum was supposed to launch from a landing craft, zip up the beach, crash into a fortified wall or gun turret and blow it to smithereens.

“The problem is, the guiding devices for later test variants were rudimentary at best,” says Curatola, “and the thing’s going to go wherever the hell it wants to go.”

Tests of the Panjandrum in 1943 and 1944 were disastrous and the rocket wheel was dropped from D-Day preparations.

Early in World War II, the Soviets invested in a novel, albeit inhumane weapon: trained dogs operating as suicide bombers.

The Soviet dogs were trained to target German tanks. They were equipped with backpacks carrying several pounds of explosives. A lever protruded upward from the backpack. When the dog slipped beneath the hull of a tank, the level was depressed, triggering the explosives.

As many as 40,000 Soviet anti-tank dogs were trained to make the ultimate sacrifice, but few reached their targets. The Nazis simply shot any dogs spotted on the battlefield, neutralizing the threat.

It looks like something out of a Bugs Bunny cartoon, but this very real rifle was Germany’s attempt to make a gun that could shoot around corners.

The Krummlauf was an attachment that added a curved section to the barrel of a standard-issue MP-44 rifle. There were two versions of the Krummlauf: a 30-degree bend for shooting around or over obstacles, and a 90-degree bend for shooting from inside an armored vehicle. The Krummlauf came mounted with a set of mirrors to aim the curved end of the barrel.

In American tests of captured German weapons, the Krummlauf performed poorly. Bullets snapped in half as they ricocheted through the curved barrel, greatly reducing the weapon’s range and accuracy. And the barrel itself would snap in half after firing only a few hundred rounds.