Maury Island incident

The Maury Island Incident, June 1947, refers to claims made by Fred Crisman and Harold Dahl of falling debris and threats by men in black following sightings of unidentified flying objects in the sky over Maury Island in Puget Sound. Dahl later retracted his claims, stating the story was a hoax. The FBI file on Crisman indicates that the Bureau quickly determined the matter was a hoax. The file noted that Dahl stated that "if questioned by the authorities he was going to say it was a hoax because he did not want any further trouble over the matter”, and that Crisman or Dahl likely made an anonymous phone call "in the hope of building up their story through publicity to a point where they could make a profitable deal with Fantasy Magazine, Chicago Illinois."

Crisman and Dahl said they were harbor patrolmen on a workboat who saw six doughnut shaped objects in the sky near Maury Island. According to Crisman and Dahl, one of the objects dropped a substance that resembled lava or "white metal" onto their boat, breaking a worker's arm and killing a dog. Dahl claimed he was later approached by a man in a dark suit and told not to talk about the incident. The story was later retold in Gray Barker's book "They Knew Too Much About Flying Saucers," which helped to popularize the image of "men in black" in mainstream culture.

The substance claimed to have been dropped by the objects was found to be slag from a local smelter. Years later, Dahl confessed to a reporter that the incident was a hoax.

...
Wikipedia