If you've spent some of the summer holidays down at the beach, you're likely to have spotted a slimey visitor on the sand.
The recent warm weather has seen a rise in jellyfish heading to shores across Britain, and many of you have been taking to the coast yourselves to see if you can find one of the creatures.
Dozens of you have been taking your cameras to the beach to snap the jellyfish in action - but you need to remember not to get too close, for risk of being stung.
If disaster hits on a day out at the beach, do you know what to do?
Most strings from sea creatures in the UK are not serious and can be treated with first aid - but sometimes you may need to visit hospital.
Here's some advice from the NHS.
What to do if you've been stung
*Get help if possible - ask a lifeguard or someone with first aid training for help
*Rinse the affected area with seawater, not fresh water
*Remove any spines from the skin using tweezers or the edge of a bank card
*Soak the area in very warm water, as hot as can be tolerated, for at least 30 minutes. Use hot flannels or towels if you can't soak it.
*Take painkillers like ibuprofen and paracetamol.
What NOT to do if you've been stung
*Don't use vinegar
*Don't pee on the sting
*Don't apply ice or a cold pack
*Don't touch any spines with your bare hands
*Don't cover or close the wound
How to avoid being stung
*Look out for beach warning signs
*Wear a wetsuit while swimming in the sea, especially during spring or summer
*Wear waterproof shoes or sandals when waling in shallow water or rocky areas
*Scuff or stamp your feet when walking in shallow water to warn sea creatures you are approaching
When to go to a minor injuries unit
*If you have severe pain that isn't going away
*If you've been stung on your face or genitals
*If you've been stung by a stingray
When to go to A&E or call 999
*If you have difficulty breathing
*If you have chest pain
*If you have suffered a fit or seizure
*If you are suffering severe bleeding
*If you are vomiting
*If you feel lightheaded