Deathcorn
Oh, those wacky guys in the OSS and SOE. The things that they could come up with, once they were in a place and time where nobody asked them inconvenient questions, like “Is that a practical idea?” or “How much is that going to cost the government?” or even “Did they ever happen to call you ‘mad’ at university?” Amazing how much leeway people get when it comes to punching Hitler.
Or, well, in this case punching Tojo. The Deathcorn Project was apparently the brainchild of one J.C. McWilliams (the OSS documentation actually redacted out all personal info, but the censors missed one entry) who was working on resistance weapons in the Pacific Theater. The project goal was to create a self-replicating, organic hand grenade; McWilliams apparently figured out how to combine a particular breed of corn with a particular kind of fertilizer to create ears that, when dried, can be lit on fire and thrown as standard fragmentation hand grenades.
Advantages: self-replicating, organic hand grenade; doesn’t register as explosives on the standard security sweeps. Disadvantages: too finicky about soil (at least by 1940s standards), did not grow well in tropical or subtropical climates, no safety pin, and the corn itself tasted horrible. Unfortunately for Mad Science hobbyists, the disadvantages outweighed the advantages in this particular case: the OSS/SOE eventually shelved the Deathcorn project and went back to making more prosaic edible, explosive flour.
The aforementioned OSS documentation includes a couple of extremely old ears of Deathcorn, packed extremely carefully in shredded paper. More interestingly: the final sheet in the file notes that several crates of viable seeds were sent to an SOE cold storage facility in Western Greenland (corn seeds can last forever, if properly frozen). Researching the ship used for transporting the Deathcorn reveals that it never actually made it to its destination, thanks probably to a German U-Boat. With any luck, those seeds are still salvageable… and, hey: what other goodies might have the OSS/SOE packed away on that voyage? Well, you never know until you look, right?