Gruff is stinky. He spends most of his time hiding from Big man. Big man gives him good tasty things so Gruff knows he must obey. He rarely ever gets washed by Big man and Gruff doesn't know how to clean himself. That is way too hard for Gruff. Gruff is not a dog. He is not a cat. He is something in between. Here on Gruffdon, a planet thriving on the waste of Gruffs, there is not an animal more revered than Gruffs. The smartest beings on Gruffdon, are Mattons, which are much like you humans, in intelligence, at least. We have round bodies and we roll rather than walk. We didn't have to discover the wheel here. Every Matton is basically a living wheel. I, myself, can't imagine another reality. Or maybe I can, but I much prefer mine.
The excrement of Gruffs is not unpleasant like the excrement from Mattons. Mattons' waste is similar to that of humans. Gruffs are special among us all. They expel liquids from two different rectums, mixing together and evaporating into a gas that we, Mattons live off of. Like, your oxygen, we live on Nytrogen. So, unfortunately we can not coexist in the same air space, unless converters are worn at all times.