Now You See it... by Richard Matheson
Maximillian Delacorte was once the world's greatest stage magician. Now a recluse, suffering from a mysterious disease, he lures his family and associates to his lonely estate for an afternoon of magic, madness, and revenge. Bodies appear and disappear without warning, severed heads speak words of hate, and nothing is ever quite what it appears. As grisly tricks lead to ever more surprising twists, not even the Great Delacorte can tell where illusion ends--and murder begins.