Perhaps The Craziest Thought Any Human Has Ever Had

TL;DR

During WWII, dentist Lytle Adams proposed strapping tiny incendiary bombs to bats to burn down Japanese cities, and the US military actually funded it.

Key Points

• 1.A dentist visiting Carlsbad Caverns conceived the bat bomb idea after Pearl Harbor. Dr. Lytle Adams, inspired by millions of Mexican free-tailed bats roosting in caves, proposed fitting them with incendiary devices and dropping them over Japan's bamboo-and-paper cities.
• 2.FDR personally greenlit the project after Eleanor Roosevelt passed Adams's memo to his desk. FDR's note read 'This man is not a nut — sounds like a perfectly wild idea, but worth looking into,' launching the officially named Project X-ray.
• 3.Harvard chemist Louis Fieser — inventor of napalm — designed sub-ounce incendiary bombs for the bats. The smallest weighed half an ounce with a 10-inch fuse; bombs were glued to the bat's chest skin with surgical adhesive and a string.
• 4.Each delivery canister held 1,040 bomb-carrying bats and was designed to release them at 4,000 feet via parachute. The bats were kept refrigerated to induce hibernation during transport, intended to wake in warmer air and disperse into buildings.
• 5.The project accidentally destroyed the Carlsbad Army Air Base when armed bats escaped and roosted under a fuel tank. The resulting fires burned down test buildings, a control tower, and a general's car — a self-inflicted success of sorts.
• 6.After $2 million spent over three years, the Navy canceled Project X-ray in favor of the atomic bomb. Adams maintained his plan could have spread fires across a 60 km diameter with fewer civilian casualties than the nukes dropped on Hiroshima and Nagasaki.