Dungeons and Dragons Satanic Panic
Though it was satire, it still caught on to people's fear of the occult. This fear led to problems with the criminal justice system. For example the West Memphis 3, 3 teens accused of murder, were prosecuted just because of people being scared of the occult. Even a policeman changed a story about the Irving Pulling case (Suicides & Harm) because he was scared of TSR suing him.