https://www.popularmechanics.com/military/weapons/a29417939/unidentified-submarine-objects/
In October 2019, U.S. Navy Commander David Fravor, who was the subject of a New York Times article about his 2004 UFO sighting, discussed a spooky new sighting a fellow pilot revealed to him after they were both out of the Navy.
According to Fravor, the eyewitness was a former pilot of the MH-53E Sea Dragon, the Navy version of the Marine Corps’ CH-53E Sea Stallion, based at Naval Station Roosevelt Roads, on the island of Puerto Rico. Twice while recovering spent practice munitions out of the water, the pilot spotted a weird underwater object.