Gangster Donkey.

Henry Winkler was the right hand man to Gangster Horse, who pretended to be Gangster Donkey to train Henry until he was ready to know that he was the real one. The real Gangster Donkey made his debut appearance in season two's "Zucchini Treats". He originally had good ideas that really would have worked for the Gang. But in his mourning after Gangster Horse's death, Gangster Donkey decided that making over-complicated plots that would almost definitely never work just went with the title. He swore revenge on Grubby and Herbert for killing his mentor and ran off with the Gang, presumable to the Donkey Den. We'll just have to wait and see when he comes back...

He lives in an alley.