If you were to go down to the beach today you may find a wobbly surprise.
Thousands of bright electric blue creatures, thought to be Velella Velella, have washed ashore after a scorching heatwave this summer.
The creatures dubbed ‘alien jellyfish’ are normally found in exotic climes like Portugal or the Caribbean but over the weekend it was St Bees beach in Cumbria that was overrun.
Louise Nicholson nearly mistook one of the strange creatures for a mound of seaweed.
Speaking to BBC Cumbria, she said: ‘There were hundreds of them and there were lots of visitors to the area taking photos.
‘They are absolutely beautiful, only about 2ins in size. It was a great find on a beautiful day.’
The organisms have a ‘sail’ which they use to travel across oceans, and normally roll into strange territories in the wake of a storm.
They are harmless to humans – but beachcombers have been warned to be aware.
Velella velella, known as By-the-wind Sailors, haven’t been swept here in such huge numbers in more than a decade.
But although the two-inch creatures are related to the deadly Portugese man ‘o war, the worst they offer people is a mild sting.
The electric blue creatures are ‘colonial hydroids’ – meaning they’re not jellyfish but a colony of tiny individual animals.
They live partly in and partly out of the water with a sail held in the wind and tentacles dangling in the water to catch plankton.
Conservationist Steve Trewhella said: ‘They only wash up after prolonged gales and storms.
‘Because they travel in the same way, in theory Portugese man o’ wars could come in as well, and that would be something to worry about. They pose a real threat and can kill people in the water.
‘We are noticing a trend in these unusual marine animals coming into our shores on a more regular basis recently. It’s because our weather appears to be changing.
‘Velella velella are deep blue or purple in colour and often cause confusion if they wash in, in vast numbers, creating a blue beach.’
Marine specialist Frankie Hobro, owner of Anglesey Sea Zoo in Bynsiencyn, said their sting is ‘mild’ in comparison to their cousins – the deadly Portuguese man o’ war.
‘If you touched your lips, face or another sensitive area, it could be quite painful and cause a tingling sensation,’ she said.
‘What is slightly worrying is that Portuguese Man o’ War are arriving earlier in the year and more frequently, overlapping with marine creatures like By-the-wind-sailors. It shows how climate change is affecting ocean currents.’
Temperatures could reach 35C in the South East on Monday, according to the Met Office, higher than forecasts for the islands of Mykonos, Rhodes and Santorini.
Much of central and southern England is set to see highs in the upper 20s to low 30s before temperatures ease slightly later in the week.
The UK Health Security Agency (UKHSA) has issued amber heat-health alerts for the East Midlands, East of England, South East and London from Monday until Wednesday morning.