Deadly creatures often mistaken for jellyfish are washing up on Britain’s beaches, sparking warnings from wildlife experts
While incidents are extremely rare, one venomous sting from a Portuguese man o'war - dubbed "floating terror" - can kill a human, even if the creature is already dead.
Stormy weather has driven the m from their ocean lairs and they are now scouring shallow waters off the UK's coast in search for plankton to devour.
Portuguese mean o'war, which can grow up to 160ft long, have recently been found washed up on Sennen Beach and nearby Portheras Cove in Cornwall, locals told CornwallLive.
The Wildlife Trust said the creatures are rarely found in Britain, though they can wash up between September to December after strong westerly winds.
Their purple bodies can grow to 12ft but their ribbon-like tentacles can can grow up to 160ft and are virtually invisible.
A Wildlife Trust spokesman said: "First of all, the Portuguese Mmman o'war is not a jellyfish. It is a colonial hydrozoan, made up of small individual animals called zooids - each with their own specific function, e.g. feeding or breeding.
"They can't live separately and function together as one 'animal'.
"The Portuguese man o'war lives at the surface of the open ocean, held afloat by a gas-filled bladder. This has a crest-like structure at the top which acts as a sail.
“They can’t swim and are at the mercy of the winds — which is why they often end up washed ashore after big storms.
“They are fearsome predators, catching small fish and crustaceans with their long stinging tentacles.
"It’s these tentacles that you need to watch out for too — they can sting long after the animal has died.”
People have been urged not to touch the creatures and to keep their pets away from any found on beaches.