Goosebumps: Phantom Of The Auditorium - A Turn of Events
Read the summary on the back cover of the book. Two sentences of the summary read: "A message appears on a piece of scenery: 'The Phantom Strikes!' A stage light comes crashing down." If you have read the book, you'd know that the message on the scenery said, "STAY AWAY FROM MY HOME SWEET HOME", not "The Phantom Strikes!" Now about the stage light, no where in the book does the narrator (Brooke) mention anything about a stage light crashing down. In Layman's terms, that event never happened in the book. Feel free to flame me if I'm wrong, but I've read the book and I know what I'm talking about.
Goosebumps Book #24: Phantom Of The Auditorium (must have read the whole book), and a very good memory of it