This question already has an answer here:
Occasionally, the resolution of a movie is that all the scifi or supernatural elements turn out to be fabricated with some conventional technical tricks. For instance, "ghosts" may have be en simulated with light effects, etc., possibly to make one or more characters erroneously believe they are witnessing supernatural happenings.
Are such works in scope for this site?
The question has already been answered positively for the related case of dreams or hallucinations. Technical trickery may or may not be treated somewhat differently, though: Dream worlds in fiction typically form some kind of universe of their own (even if said universe is not a physical reality in-universe), whereas the described tricks are more about misleading the protagonists and the audience likewise.
At the same time, I could think of some cases that would make this kind of works hard to exclude completely:
- A work may leave it open to interpretation whether everything was fake, or whether something supernatural was going on after all.
- Especially in story ID questions, askers may not be aware of the work's resolution and the supernatural or mundane nature of things presented earlier in the work.