What are the strangest propaganda campaigns in ur country that actually changed public opinion?

In some Egyptian villages, older people used to tell children that the evil lived in the Nile at night and would kidnap kids who went too close to the water. The story wasn't meant to be true, but it was used to scare children so they wouldn't go near the river and risk drowning and go in night

Does your country have similar stories or organized propaganda from govarment ?