VIDEO: Giant jellyfish swims next to diver off English coast

Just when you thought it was safe to go back into the water, a giant jellyfish has been spotted off the southwestern coast of England.

The diver was in shock swimming alongside the human-sized jellyfish, which can grow up to 3.5 feet and weigh 55 pounds.

The "barrel" jellyfish is the largest species of jellyfish in British seas. Seeing one, though, is extremely rare.