Raining Cats and Dogs

Someone once told me that it was raining cats and dogs outside.  I looked out the window, and it looked like it was just water.  I told him as much, but also said that it could be arranged for it to rain cats and dogs, as I had just recently acquired my blimp pilot's license, but I suspected that such action might fall under some sort of animal cruelty laws.  Some people have strange ideas about how to have a good time...