BEACH-GOERS are being warned to keep their distance, as a ferocious jellyfish- like creature capable of delivering a fatal sting has been washed up on Pembrokeshire shores.

An Atlantic Portuguese man o' war, also known as the man-of-war, blue bottle, or floating terror, was spotted on Tenby's South Beach yesterday (Thursday).

Members of the public are being advised to keep their eyes open, as a single Portuguese man o' war can be followed by others in the vicinity.

Because a stranded Portuguese man-of-war looks a bit like a deflating purple balloon with blue ribbons attached, it may attract the curiosity of children or dogs and beach goers are warned to be on their guard.

The creatures, which can deliver a powerful, and sometimes, fatal sting, are not actually a jellyfish but a collection of interdependent organisms.

It is Cornish pasty-shaped, with a transparent purple float and blue, tentacle-like fishing polyps which hang below and can be tens of metres long.

They live on the surface of the ocean and the gas filled bladder on top of act as a sail, meaning the creature travels according to the winds, currents, and tides.

They are most commonly found in the open ocean in in tropical and subtropical regions but there have been sightings further north.

Their sting is sting said to be ten times stronger than an ordinary jellyfish and can cause an allergic reaction.

Treatment for the sting - which leave whip-like, red welts on the skin - involves washing the affected area with salt water and then applying ice to dull the pain. Anyone who is stung is advised to seek medical advice.

Anyone spotting a man o' war should not touch it and report it to the beach owner or the local authority.

Sightings can also be reported by clicking on the wildlife protection link at www.mcsuk.org. A guide for identifying the Portuguese man-of-war can also be found on the website.