A play by Charles Dickens. The Haunted Mansion ride at Disneyland. A hologram of a famous dead pop singer. They’re all connected by a simple magic trick called Pepper’s Ghost. What’s most remarkable about this illusion is that it hasn’t changed much in over 160 years. I talk with Jim Steinmeyer and Ben Schrader, both designers of theatrical special effects, about why a Victorian magic trick is more popular than ever at modern theme parks and other live entertainment venues.