The rare creature is thought to be a Lion's Mane - a breed that can potentially cause serious harm to humans if they're stung.
Over the past two weeks many smaller jellyfish have been spotted on the picturesque beach in Saunton, North Devon.
Locals say the latest is the largest by far to wash ashore.
Many smaller jellyfish have washed up on the beach over the last few weeks
A sting from the Lion's Mane jellyfish can result in blistered red skin and intense pain but most healthy people will simply have to wait for the pain to pass.
However, in rare cases it may lead to muscle contractions and cramps, respiratory problems and even heart attacks.
Retired businessman Justin Wilks, 53, said: "It is starting to become a real issue.
"I'm down here most mornings with my dog and we've been dodging them for the last week or so.
"We normally get jellyfish on the beach in the summer but this is really early to start seeing them.
The latest freak discovery was found on Saunton beach in North Devon
The creature measures around 3ft in width
"I'm concerned this means more jellyfish than ever before will be in our seas over the summer months."
Local cafe owner Julie Pearce, 43, added: "We are already having some real monsters wash up on the beach.
"The horrid things creep me out and make me think twice about going into sea".
The lion's mane jellyfish, also known as the giant jellyfish or the hair jelly, is the largest known species of jellyfish.
The lion's mane jellyfish is also known as the giant jellyfish or the hair jellyfish and is the largest known type
It is common in the English Channel, Irish Sea, North Sea and in western Scandinavian waters.
They can grow a bell diameter of over two metres and have tentacles over 40 metres long which catch their prey such as prawns, shrimps, small fish and other jellyfish.
They are usually an orange, red or yellow in colour, with a shallow umbrella.