A lone bluebottle is terrorising the shores of New Jersey in the US.

One of the marine creatures, so synonymous with summer at Australian beaches, washed up on the sand in Harvey Cedars on Long Beach Island on Sunday. Panic ensued.

So great was the concern that it prompted a warning from lifeguards, scores of news stories about the creature, known in the US as a Portuguese Man o' War, while "Harvey Cedars, New Jersey" was trending on Facebook in the days after the discovery.

One NBC reporter crossed to the studio live from the very beach where the bluebottle washed up, describing it as a "creature with a sting so severe and so painful it can be deadly". The segment was entitled "Scare at the shore".