The Marine Conservation Society are warning members of the public about Portuguese Man-of-War washing up on UK beaches.
There have been several sightings of the potentially fatal animal on beaches in Cornwall and also on the Isles of Scilly recently.
See also: Venomous Portuguese man-of-war washes up on Cornwall beach
See also: Holidaymakers warned over surge of deadly creature on British beaches
Posting on their Facebook page, the Marine Conservation Society said: "Physalia physalis are only occasionally reported in UK waters with the last significant UK strandings in 2009 & 2012."
They described the appearance of the animal, saying: "A Cornish pasty-shaped, transparent purple float is visible on the water's surface whilst the blue, tentacle-like 'fishing polyps' that hang below can be tens of meters in length. Look but don't touch and report to us pronto."
Dr Peter Richardson from the society told the Telegraph: "We don't receive reports of Portuguese Man-of-War every year, but when we do they can turn up in big numbers, usually around about this time of year."
He added: "With the earlier strandings in Ireland, these recent sightings could herald the arrival of more of the creatures as they get blown in from the Atlantic."
The unusual looking creature is made up of four separate 'polyps' and they are generally a blue-purple colour.
Their tentacles can reach as far as 50 metres underwater and are filled with venom that can kill fish.
While these stings are incredible painful for humans to endure, they are not generally deadly.
The Marine Conservation Society is asking members of the public to report any Portuguese Man-of-War sightings and attach a picture if possible. You can do so at www.mcsuk.org.