The Poodle!
The book opens with an epigraph from a scene in Johann Wolfgang von Goethe's drama, Faust.
'...who are you, then?'
'I am part of that power which eternally wills evil and eternally works good.'
The question is asked by Faust and the answer comes from the demon Mephistopheles.
As you may or may not have learned, the demon Mephistopheles appears in Faust as a poodle.
The symbol of the poodle pervades the entirety of Chapter 23. Margarita must wear a heavy necklace with the image of a poodle, and she rests her foot on "a cushion with a gold poodle embroidered on it."
The poodle is a direct connection to the devil. In Faust, Faust sells his soul to the devil exactly how Margarita sells her soul to Woland and becomes a witch.
Behemoth, the enormous black cat, is also a sort of parodic symbol of the demonic black poodle.
