Beaches around the country have been overrun by hordes of blue jellies which have washed up on the shores.
Sightings of the jellyfish-like creatures have been reported across the West Coast, including in Taranaki.
Marine biologist Emily Roberts, who works for Dotterel Defenders, saw several of the local beaches were covered with the strange creatures on Saturday, which were identified as by-the-wind sailors (Velella velella).
"The beach was just bright blue. There were just millions and millions of the by-the-wind sailors just washed up," she told Newshub.
"We've seen a few wash up before, but nothing on this scale."
The creatures have washed up over the last few days. On one beach they've already started to decompose, Ms Roberts said.
"The beach looks like it's covered in snow, it's totally white. You just end up where the tentacles break down so you end up with the clear bits sticking around."
Ms Roberts said they were part of the blue fleet organisms, which includes bluebottle jellyfish.
They earned their name because they float on the ocean's surface and are blown about by the wind.
But unlike bluebottles, the by-the-wind sailors don't sting too badly.
"They've got the little stinging cells in them... You can touch them, but if you do, make sure you wash your hands afterwards," Ms Roberts said.
"If you rub your eyes with the toxins in them, you can end up with sore eyes and your eyes swelling up."