Forget sharks, Spain just closed beaches over a creature no bigger than your fingertip.
Fez– In Spain’s sunny southeast, swimmers were asked to stay out of the water this week after an unusual visitor appeared on the shoreline, and it’s far smaller, stranger, and more dangerous than its mythical name suggests.
Authorities in Guardamar del Segura, a coastal town in Alicante province, temporarily closed all local beaches after spotting two tiny sea slugs known as “Glaucus atlanticus”, or the “blue dragon.”
The order came on Wednesday, when local police posted an urgent warning on Facebook citing public safety concerns.
Despite its delicate, almost otherworldly look, the blue dragon is anything but harmless.
Measuring barely three centimeters long, it floats upside down on the ocean surface, feeding on venomous creatures like the Portuguese man-o’-war.
In an impressive trick of marine chemistry, the slug stores and concentrates its prey’s toxins, giving it the ability to deliver a far more potent sting than its size would suggest, enough to paralyze prey hundreds of times larger than itself.
“Physical contact with this animal can be dangerous and may cause painful skin burns,” the Guardamar police wrote, urging beachgoers not to touch any strange-looking creatures they might see washed ashore.
Even gloves are no protection, they added, since the venom can pass through fabric on contact.
The ban on swimming was lifted by Thursday, but authorities remain on alert. Mayor José Luis Sáez asked residents and tourists to report any new sightings immediately and to avoid handling the creatures altogether.
Those stung are advised to rinse the affected area with seawater, not fresh water, and seek medical attention if symptoms persist.
Otherworldly and dangerous
Although these slugs look like mythical beasts that slipped out of a fantasy novel, they are real animals that drift with ocean currents in temperate and tropical waters.
They’re rarely seen in the Mediterranean, making this week’s discovery especially unusual.
Most sightings occur in the Atlantic, Pacific, and Indian Oceans, where warm waters and steady winds push them toward the surface.
The beaches around Alicante are usually known for sun-soaked holidays rather than dangerous wildlife.
The region’s rugged cliffs, clear Mediterranean waters, and long sandy stretches make it one of Spain’s most popular tourist destinations.
While jellyfish occasionally interrupt summer swimming, a blue dragon encounter is almost unheard of.
Experts say these slugs don’t actively seek swimmers; they simply go wherever the tide carries them.
But their striking appearance, shimmering silver on one side, electric blue on the other, often tempts curious beachgoers to pick them up, a mistake that can lead to an excruciating sting.
For now, life in Guardamar del Segura has returned to normal, with swimmers back in the water and lifeguards watching closely.
But the brief closure was a reminder that even Europe’s most familiar coastlines can hold surprises.
The incident also hints at broader changes in marine ecosystems. Scientists are studying whether shifts in ocean currents, rising sea temperatures, or other climate-related factors are carrying rare species into new habitats.
While there’s no evidence yet of a lasting pattern, these unusual sightings are becoming more frequent across Europe’s coasts.
So, if you find yourself on Spain’s Mediterranean shore and spot what looks like a tiny dragon gliding on the tide, admire it from a distance.
