The Cheshire Cat is a fictional cat appearing in Lewis Carroll's Alice in Wonderland. It appears and disappears at will, engaging Alice in amusing but sometimes vexing conversation. The cat sometimes annoy Alice when pointing out philosophical points. It does, however, appear to cheer her up when it turns up suddenly at the Queen of Hearts' croquet field, and when sentenced to death baffles everyone by making its body disappear, but its head remain visible, sparking a massive argument between the King, the Queen and the executioner about whether or not something that does not have a body can indeed be beheaded.
At one point, the cat disappears gradually until nothing is left but its grin, prompting Alice to remark that she has often seen a cat without a grin but never a grin without a cat. This has become a point of notability for the cat: most people remember it most strongly performing its vanishing act.