Rare Jellyfish Stings Independence Day Swimmers With Its 25-Foot Tendrils (VIDEO)

A "hula-hoop" sized rare black jellyfish (or black nettle) was stinging California swimmers over the 4^th of July weekend.

Joe Richman spotted the giant jellyfish while kayaking, CBS8 reported.

"In 30 years of diving and fishing off San Diego, I've seen a lot of cool things and this ranks up there as one of them," Richman said.

During the holiday weekend some swimmers came out of the water with "dark membranes clinging to their body," News 10, and ABC affiliate, reported.

The black nettle's tendrils can grow to 25 feet or longer.

The species has only been named since 1997 but pictures have been floating around of the elusive nettles since the 1920s, and only very recently have there been sightings in southern California, Montery Bay Aquarium reported

Nigela Hillgarth of Birch Aquarium said the unusual sightings (and stinging) could be thanks to warm ocean temperatures, reported News 10.

The jellyfish made a dramatic appearance around San Diego in 1989, but disappeared soon afterwards, the Montery Bay Aquarium reported. Ten years later the black nettles came back with a vengeance, and now they have returned again.

The increased number of nettles could be an indication that humans have changed the condition of the oceans by increasing the amount of organic material which provides more nutrients for multiple types of aquatic life.

The organic substances can feed plankton, causing their population to rapidly grow. This means more food for the black nettles, and increased population int them as well.

The jellyfish are ominous looking, but their sting is not likely to be fatal.

"They are not likely to kill you. They are not a deadly jellyfish, but they can give you a painful sting," Richman said, according to the International Business Times.

Nettles are protectors of the meek Pacific butterfish. The fish hides inside the bell of the nettle when it senses danger, and eats plankton that the jellyfish collects, according to the Montery Bay Aquarium.

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