An undulating ribbon of silver surprised divers near northern New Zealand in October — but not so much that they couldn't get it on video.

The resulting film shows a floating "feather boa" of the sea, properly known as a pyrosome. The 26-foot-long (8 meters) tube is not a single creature, according to The Washington Post, but rather a colony of tiny creatures called tunicates.

"I've always wanted to see one," videographer Steve Hathaway told The Post. [Gallery: Jaw-Dropping Images of Life Under the Sea]

This 26-foot-long (8 meters) tube is not a single creature, but rather a colony of tiny creatures called tunicates.
This 26-foot-long (8 meters) tube is not a single creature, but rather a colony of tiny creatures called tunicates.
Credit: Steve Hathaway/Caters News Agency

Tunicates can be either free-floating or anchored to the seafloor. Either way, they filter feed on plankton. Pyrosomes can be made of different species of tunicates, but large ones are often formed by a variety called Pyrosoma spinosum, which also emit a gentle bioluminescent glow.

Hathaway told The Post he and his friend Andrew Buttle ran across the colonial creature while shooting underwater footage near White Island, New Zealand, on Oct. 25. Buttle's family owns the island, which is also known as Whakaari, but it is open to public tours.  

The pyrosome was below Hathaway on the ocean floor when he first spotted it, he said, and he moved quickly to train his video camera on the colony.

"I know nature waits for nobody, and I couldn't let this opportunity pass me by," he told The Post.

Each tiny tunicate that makes up the giant pyrosome looks like a simple white rod, though they are in fact complex: these animals have a spinal cord. They reproduce by cloning, so each one in the colony is genetically identical to all the others — though when two separate colonies meet, they can reproduce sexually as well. According to Oceana.org, a colony could theoretically live forever, adding new clones as old ones die, and growing and shrinking in response to conditions.

Two divers were surprised by this gorgeous "feather boa" off northern New Zealand.
Two divers were surprised by this gorgeous "feather boa" off northern New Zealand.
Credit: Steve Hathaway/Caters News Agency

Colonies take the shape of a hollow tube and can grow to 60 feet (18 meters) in length and be wide enough for a diver to swim through. However, you shouldn't try, according to a 2013 article in Deep Sea News. There has been one report of a dead penguin found inside a large pyrosome. The unfortunate bird apparently got stuck and was unable to turn around or break free from the colony. Though divers describe pyrosomes as feeling fluffy like a feather boa, they're quite strong, according to the piece. A 2017 article by Reuters reported a sudden spike in small pyrosomes along the West Coast in the United States, which clogged fishing gear with a gummy-like substance

The appearance of these West Coast pyrosomes — far outside their normal, tropical range — is still a mystery. According to the National Oceanic and Atmospheric Administration, in the summer of 2017, five minutes of towing a net off the coast of Oregon turned up a whopping 60,000 pyrosomes.

Originally published on Live Science.