Cats have nine names, as well as lives.

This cat came to me bearing the name Hecate.  My daughter's choice, which I found a bit pretentious for a mere house cat.  After a few amusing mishaps, such as falling off a table, falling off the deck, I took to calling her Stupid Beast.  This worked, the cat would even come when I called Stooopid Beast from the deck.  As time went on, Stupid Beast spent more and more time racked out flat on the rug.  I began calling her Flat Beast.  I considered Flat Cat, but I feel Robert A. Heinlein has some ownership on that name.  Variations such as Her Flatness, just plain Flat, followed.  Also Round and Flat, abbreviated to RAF.
   This might be family tradition.  We had a family cat, a Siamese, who came into the family named Cleopatra.  This did not last, and we kids called her Puddy Tat.  Then after Puddy Tat put on weight, my Father started calling her BasketBall.