A running shoe surfaced at Ocean Beach in San Francisco on Sunday – attached to a human foot. The rest of the body is nowhere to be found.

According to the San Francisco Chronicle, someone found the foot washed up on shore and called the National Park Service beach patrol about the incident.

Whatever severed the foot from the body in the first place is thought to have occurred awhile ago. An investigator with the San Francisco Office of the Chief Medical Examiner, Mark Powning, reported that, "What we have is a human foot, with some associated tissue, inside of a shoe. It probably was rolling around the seabed for awhile.”

The Associated Press reports that the discovered shoe was a green-and-black-mesh Puma running shoe, size 11 ½.

According to sfist, the wash-up isn't all that rare. Thirteen or more feet have been discovered in the Pacific Northwest from 2007-2012. Perhaps this is because the shoe preserves the foot from decomposing completely – feet have been known to last several years even after a person has died.