Visitors to the coast at Tremadog Bay in north Wales have been warned about a swarm of jellyfish in the area.
A moon jellyfish on Blackrock sands
People have been warned not to touch the jellyfish, after about 1,000 of came ashore at Blackrock sands in Morfa Bychan, near Porthmadog.
According to Gwynedd council, the jellyfish are able to sting.
It is believed that the moon jellyfish (aurelia aurita) were brought to the area by warm sea currents and the prevailing wind.
The moon jellyfish are the UK's most common and the species can arrive in areas in massive numbers.
Widespread around the coast of Britain, it uses its stinging tentacles to capture plankton.
Maritime officer Barry Davies, of Gwynedd council, said the jellyfish should be avoided by people visiting the beach.
The moon jellyfish is the UK's most common species
He added: "They deliver a mild sting if touched. It is not too dangerous, but it could be worse for people who are allergic.
"We would advise people not to touch them, turn them over or play with them.
"People swimming should be OK, but obviously avoid any swarms that may be in the water."
Moon jellyfish grow up to 40cm, are transparent with purple rings and are shaped like an umbrella.
Mr Davies said they would either move along by themselves or would be taken from the area over the next couple of days.
He said: "There are about 1,000 on the tide line at Blackrock sands and some in Harlech."
"It's quite a common occurrence - they come in on the Gulf stream and with the warm weather.
"We'll either clear them up, or they'll disappear as the weather changes over the next few days."