The "Bat Bomb" was an alternative to the Manhattan project where a million bats would be dropped from special delivery capsules with each bat carrying a napalm based incendiary device. The bats would fly into Japan's many wooden buildings and a timer could cause them to burn and start fires. The project was deemed successful. However by the time of completion the atomic bombs were ready and the use of bats as WMD was obsolete.
But what if this relatively low-tech (compared to the Manhattan project) system was ready in early 1942 and in time for the Doolittle raid on Tokyo? Instead of a publicity stunt doing little damage, would the Bat bomb shorten the war?
According to wikipedia:
"The NDRC (National Defense Research Committee) observer stated: “It was concluded that X-Ray (code name for Bat bomb project) is an effective weapon.” The Chief Chemist’s report stated that on a weight basis X-Ray was more effective than the standard incendiary bombs in use at the time. “Expressed in another way, the regular bombs would give probably 167 to 400 fires per bomb[er] load where X-Ray would give 3625 to 4748 fires.”"
The plan was to use 10 B-24 Liberators for the mission. They would fly out of Alaska. Every bomber would be able to cover an area of 40 miles in diameter. In theory, assuming all bombers do their job properly. The bombers should be able to start a total of between 36,000 to 47,000 fires.
The Doolittle raid used 16 B-25 Mitchells. That should give it comparable payload to 10 Liberators in long range configuration.