As opposed to your normal, ordinary illusions:
It's a cheapy. It ought to be a long snooze; the lead actor is a gosh-gee-whiz teen trying to investigate his father's death, which is Hardy Brothers territory. But it's good enough. It begins with a dream sequence, as the teen dreams he's wandering through Smoky Dream Land while Schumann's piano concerto plays:
Most people don't see themselves in dreams, but never mind. He wakes with the certain belief that a strange man will soon enter his family and try to marry his mother and kill her. His friends say gee, pal, that's crazy! But when he returns home from a fishing trip, Mom has a new friend:
Welcome to Cadville! The entire movie consists of the kid trying to get the goods on the guy to validate his dream. It moves along well; the bad guys are bad, the good teens earnest and clever, and the Schumann gives the movie a certain tragic dread. But now and then you can tell they're padding it a bit, and amping up the suspicion a bit too much.