More Animals That Go BOOM!

Wiki:

Exploding rats were a weapon developed by the British Special Operations Executive in World War II for use against Germany. Rat carcasses were filled with plastic explosives. The idea was that when what seemed to be a dead rat was discovered in the boiler room of a factory, the stoker tending the boiler would likely dispose of the unpleasant discovery by shoveling it into the furnace. The dummy rat would explode, causing significant damage. However, the first shipment of carcasses was intercepted by the Germans, and the plan was dropped. The Germans exhibited the rats at top military schools, and conducted searches for further exploding rats. (C.f. coal torpedoes.)