breakfast at tiffany's (1961)

Cat.
'Poor slob without a name', as Holly Golightly the central character says of her pet cat. In both the book and the film the cat has a central role, especially the end, when Holly throws Cat out of a taxi into the rain, in a fit of peak. Here the film differs from the book as Holly realises the error of her ways and is tearfully re-united with Cat.
The cat with real personality was Orangey, a star of numerous films including Rhubarb and Comedy of Terrors.