Kiwis are being warned to watch out for bluebottle jellyfish (katiaho) washing up on beaches across the country.
It comes as Surf Life Saving is seeing an increase in people being stung by the venomous sea creature.
And though not generally deadly, the stings do need to be taken seriously.
Pictures show thousands of bluebottle jellyfish lying on beaches in Nelson.
While they may look beautiful, they're actually dangerous due to their long and venomous tentacles which still sting long after the marine creatures die.
"We've seen them on our main Tāhunanui Beach, also out Bolder Bank, but we are expecting them right across the region," said Nelson City Council Deputy Mayor Rohan O'Neill Stevens.
That's forced Nelson City Council to issue a warning to locals and visitors to be extra careful of these critters lurking around beaches - especially as summer ramps up.
"If you do see bluebottle jellyfish, keep your distance. Their tentacles can be up to 10 metres long and hard to spot, and if you are taking your dog for a walk keep them on a lead," Stevens said.
And there've been sightings of the poisonous jellyfish all over the country lately as they tend to move towards warmer water in search of food.
"Certainly in the last week Raglan has had about 40 stings," Surf Life Saving spokesperson Ollie Eadie said.
Bluebottle stings aren't deadly to humans, but they can cause intense pain which can last anywhere from a few minutes to a few hours. They can also cause a nasty rash and an allergic reaction.
Eadie is a surf lifeguard at Muriwai Beach - an area notorious for the stingers.
He said those who get stung shouldn't panic.
"The most important thing you can do is remove the stinger as quickly as you can and hold it under warm water."
Some simple advice worth remembering when you head to the beach this summer.
