A pair of Long Island, N.Y., residents woke to a noise that sounded like something crashing through their house early Sunday.
"We both woke up to a very loud bang. I looked around—no breeze, no rain, nothing," homeowner Lois Farella told CBS Local New York as she pointed to a basketball-sized hole in her roof.
Next door, Ann Grace's roof on Home Street was also ripped apart.
"It's a very huge hole. It did a lot of damage through heavy wood. I can't imagine if it hit a person," Grace told the TV station.
Upon inspection Grace's roofer found a brown, wet stain in her attic where something had ripped through an inch and a half of shingles and wood.
"It's hard to understand what could have done this. It had to have come from a plane," roofer Bryan Lanzello told CBS Local New York. "A bird couldn't have done it."
So the FAA investigated the incident as possibly involving blue ice.
"Blue ice" is a euphemism for the mixture of frozen human waste and industrial-strength chemical that occasionally drops from planes' waste tanks.
Waste shouldn't be released from an airliner during flight. However, a faulty waste tank can come open, causing the leakage to freeze at high altitudes on the exterior of the airplane, Life's Little Mysteries explains.
As the plane starts to descend, the frozen chunk begins to warm and can drop from the aircraft.
FAA Eastern Region office spokeswoman Arlene Salac told Life's Little Mysteries, "If it's a large enough chunk of it, it falls off down to the ground. It does definitely occur."
But in this case she says blue ice is not to blame.
"Inspectors went out there today and it doesn't appear from the information we have at this point to be a case of blue ice," she said. "Whenever we have these cases we pull the radar tracks over the residents and there weren't any aircraft going over that house at that time. The closest one was 3 miles away, so it's not a case of blue ice, but we don't know what happened to the house."
It's not from a bird. It's not from a plane.
It's still a mystery.