The Hooper was the name given by local residents to a mysterious cloud of fog that often hovered over the Cowloe Rock, near Sennen Cove in Cornwall. During the day it gave off a mournful hooting sound, and by night it emitted showers of sparks, as if there was a fire burning inside it.
Locals believed that the mist shrouded a spirit, come to warn them of approaching bad weather, and were prevented from going to sea by an invisible force emanating from the cloud.
One day a fisherman and his son decided to get to the bottom of the mystery, and rowed out to the cloud. They were last seen flailing at the mist as their boat faded from view. Shortly afterwards the Hooper appeared to dissolve, never to return, leaving no trace of the fishermen or their boat.