The authorities in Granadilla de Abona on Tenerife are warning tourists and locals not to bathe on two beaches in the community of El Médano on the island's southeast coast.
The warning comes after specimens of the violet snail, also known as the blue dragon, have been found in the area. The invertebrate animal is small, usually only a few centimeters long, but has a powerful venom that can cause severe skin irritation and allergic reactions.
"Therefore, we recommend that you avoid the beach and follow the authorities' advice," writes the municipality on Facebook.
The violet snail floats on the surface of the sea and often lives on other large organisms, such as jellyfish and Portuguese man-of-war.