Unbelievably, every once in a while, a dead whale will actually explode all by itself. It happens because of a build-up of gas as it decomposes. According to the "Exploding Whale" page of Wikipedia, it happened in B.C. once; blubber "hung in the trees for weeks." And in 2004, the biggest whale carcass ever found in Taiwan exploded as it was being carried through a city on the back of a truck, splattering onlookers with blood and intestines and goo. You can read the BBC report on that here.