Old Syko: it was strictly by accident. It was during the war and some of us were attempting to develop 'a better mousetrap'. Actually, we were trying to develop a smaller anti-personnel mine using empty beer cans, some field expedient plastique or issue stuff if we had lots around, a spot or two of field expedient napalm, some screening wire. some copper wire, a detonator and a d-cell battery. If we could get the wires to connect when the rat attempted to pull the bait up out of the can it would set off the detonator that would detonate the plastique and ignite the napalm and presto, cooked rat for our Mountainyard troops. It didn't always work that way but the same thingwould happen if you were unlucky enough to step on it....
Now, we had caught the rats and caged them and set up just beneath the top of a trench berm - the bad guys were shootin at us and we were shootin back. The rats were nervous, like democraps or libruls when things get hot and they began to f_ - oops, expel gas and you could smell it. When charlie would open up on us with is green tracer 7.62x54R rounds, those that passed over the rat cage seemed to 'flash' a bit, which we thought scientifically interesting. So we made the rats more nervous by bringing in the Mountainyard 'chef' and when those rats really began to 'toot' the air over head was literally flashing in concert.
End of story is that as a anti-personnel mine we were told it was against the Hague Convention to use flammable anti-personnel mines, so we cooked the rats instead.............................