The Lathe of Heaven - movie

https://en.wikipedia.org/wiki/The_Lathe_of_Heaven_(film) IMDB

George Orr, a man whose dreams can change waking reality, tries to suppress this unpredictable gift with drugs. Dr. Haber, an assigned psychiatrist, discovers the gift to be real and hypnotically induces Mr. Orr to change reality for the benefit of mankind

with bizarre and frightening results.

The device where the shrink manipulates these dreams to try to remake reality is kind of like a Monkey's Paw of unintended consequences. Such as trying to fix racism and everyone in the world having grey skin.