The Cash-Landrum incident

Betty Cash, Vicki Landrum and Landrum's young grandson said a diamond-shaped object spouting flames hovered over a Texas road near Dayton in December 1980. They later reported illnesses they linked to it.

Skeptoid's Brian Dunning gives the basic story. On 29 December, at around 9 p.m., Betty Cash and Vicki Landrum were driving with Landrum's grandson, then six, on a straight road through thick trees near Dayton, Texas. They saw a very bright light ahead that seemed to be shooting out flames, stopped the car and stepped out. They described a big diamond-shaped object about as large as a water tower, hanging near the treetops and rising and falling as it fired flames. Discovery UK's feature Highway Encounter adds that the three were then surrounded by helicopters.

Texas Monthly reports that Cash stayed outside the car longest and was admitted to hospital nearby with burns. According to the magazine, all three had symptoms that looked like radiation sickness, among them burns, blisters, nausea, rashes, headaches, sore eyes and loss of hair and fingernails. Cash was later found to have breast cancer, and Landrum was left with severe cataracts. Cash told reporters she had never believed in UFOs and was the first to laugh at them, and that she was now afraid to look up.

The witnesses took their case to court. Wikipedia records that a federal district judge dismissed it on 21 August 1986, persuaded by testimony that no U.S. government agency owned such a craft and that no military crews had flown the helicopters they reported.