Character in: Wonderland
The Cheshire Cat is famous for its ability to appear and disappear at will and for its enormous grin. In fact, sometimes the entire Cat disappears, leaving only the grin behind. The most important thing the Cat does is tell Alice that everyone in Wonderland is crazy – even her. Alice has trouble accepting this at first, but the reader has been expecting it for some time. Alice is impressed by the cat's shoot-from-the-hip (or in this case, from the grin!) honesty. Throughout the rest of her adventure in Wonderland, Alice will look anxiously around her for the Cheshire Cat, hoping for more advice or at least intelligent conversation. And, of course, we already know that Alice is partial to cats, since she's always talking about her favorite pet, Dinah.
The name "Cheshire Cat" is a contemporary Victorian joke that most modern readers miss. "Grin like a Cheshire Cat" was a saying at the time, although nobody really knows where it came from. One theory is about the famous cheeses in the town of Cheshire, which, the story goes, were made in the shape of cat faces to amuse buyers. The Cheshire Cat is like one of these come to life. This also explains why the Cat's body will disappear, leaving only its head behind – the cheeses were shaped like the face, not the entire cat. Perhaps the appearance of the grin without the rest of the cat is a joke about eating part of the "face" of cheese and leaving the rest.