Magic (1978)

The schizophrenic ventriloquist and his caustic dummy has been a staple of movie horror since the year dot, probably seen to best effect in the 1945 compendium film "Dead of Night" with Michael Redgrave as the poor possessed dupe.  This riff on the same theme might have been a waste of time were it not for the bravura performance from Anthony Hopkins, who does both his own voice and the dummy's.  In fact he is the whole show, and neither Burgess Meredith as his sharp agent who thinks he needs pyschiatric help nor Ann-Margaret as his over-the-hill sexpot high school sweetheart stand much of a chance against him.  In the end one just can't tell who is the dummy and who is not.  Written by William Goldman and based on his own book, the theme is that we all need magic in our lives -- but magic is, after all, an illusion.