Lifeguards have issued a warning following "several reports" of Portuguese man o' war being washed up along Gower beaches.
It comes after an "unusual amount" of smaller and "baby" marine creatures have been reported to volunteer group - Langland Bay Lifeguards - with sightings also made in Oxwich, Llangennith and Crofty.
Often mistaken for jellyfish, but actually a colony of organisms all working together, known as a siphonophore, the beings have also washed up along North Wales beaches where they have been labelled as a 'floating terror' often being mistaken for plastic.
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Now, volunteer lifeguards at one of Swansea's most popular coastal holiday destination have urged caution and to recognise the dangers posed by them. One sting from the marine creature can cause excruciating pain to both animals and humans and even kill in some very extreme cases - even if it is already dead.
The "unusual amount" of younger Portuguese man o' war posed significant danger to sea dippers, dogs and children, they said.
"We usually get 1-2 reports a year and that isn't typically in the winter so it is quite unusual to find," said Andy Parkinson, a volunteer lifeguard coach.
"When we made that post warning people, we had further people contact us raising awareness that they have been spotted in Caswell, Rhossili and Port Eynon
"We have never seen anything like this before, baby ones or smaller ones in this scale, and at this time of year - with them being in this quantity there are additional risks to sea dippers with their exposed skin, not to mention dogs and children being curious.
"It's an unusual one, it's rare that people get stung but it's important that people are aware what to do in that situation. The wise old tale of weeing on it is just plain wrong" he added.
It is not yet understood why these younger marine creatures have appeared during these seasons but there is speculation as to whether rough seas caused by Storm Eunice played a factor.
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