Killer jellyfish have been spotted in the UK, off the coast of Cornwall.

Lion’s Mane jellyfish, which can grow up to 8ft in diameter, were seen in a swarm by a diver looking for sharks.

Apparently, they have been attracted by an abundance of giant plankton to feed on.

Tentacles of the Lion’s Mane can reach up to 10ft long and are covered in stinging cells that paralyse their victims, leading to suffocation and heart attack.

It’s all pretty exciting for the Poms, whose most frightening animal is usually the Queen’s corgi.