According to scientists, a swarm of the jellyfish, Portuguese Man o’ War, will invade the shallow waters of the Mediterranean Sea this summer, posing a threat to holidaymakers.

This will be the first time in 10 years that the potentially deadly jellyfish will make a comeback to the waters along the Costa del Sol; therefore swimmers are warned to be vigilant when taking a dip over the next few weeks.

These sinister creatures carry tentacles of up to 30 yards long and carry a sting which is 10 times stronger than the average jellyfish and in some cases, this can cause heart failure in victims who are allergic to the sting.

The Spanish authorities are preparing defenses in order to tackle the problem; nonetheless, bathers are advised to be extra careful.