The Bat Bomb

(Wikipedia) Bat bombs were an experimental World War II weapon developed by the United States. The bomb consisted of a bomb-shaped casing with over a thousand compartments, each containing a hibernating Mexican free-tailed bat with a small, timed incendiary bomb attached.
Dropped from a bomber at dawn, the casings would deploy a parachute in mid-flight and open to release the bats, which would then roost in eaves and attics in a 20–40 mile radius. The incendiaries would start fires in inaccessible places in the largely wood and paper constructions of the Japanese cities that were the weapon's intended target. Continued