Simon’s Cat is a charming, yet mischievous cat that lives with Simon Tofield, an English animator. He made his first appearance online, in a film called 'Cat Man Do'. Since then he has also appeared in his own books, game and comic strip.
Most importantly, he appears in this Christmassy video:
And best of all - all the sounds you hear in the video are made by the real-life cat Simon. What's not to love?