>>42495880
This is something i've thought and fantasized extensively about over the years. In a lot of cartoons, rancid smells can be seen eating through materials and melting through them like an acid. But in others, things just simply drop dead from the smell. Like in Total Drama Island or Shrek, which i always imagined to be from high levels of H2S gas.

So, i suppose it could be a mix of both. Like in this clip from of bad breath in Catscratch.