A filmmaker testing out a newly launched camera during a kayaking trip captured an incredible sight: a seal slapping a fellow adventurer with a live octopus.

Taiyo Masuda, 23, says he was on a GoPro-funded kayaking trip off the coast of New Zealand on Sept. 22 when he shot the now-viral video.

It happened in an instant: A seal surfaces near a kayaker, octopus in tow. The seal whips its head, smacking the boater with the mollusc. The man is left stunned.

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Yahoo reports that man was Kyle Mulinder, and he told the publication he was just as stunned as he looked in the video: "I was like, 'mate, what just happened?'"

There is an explanation, according to Rochelle Constantine, an associate professor at School of Biological Sciences at the University of Auckland.

It's not a pleasant one.

The seal was not intentionally trying to slap Mulinder in Constantine's view. The man was likely just in the way.

Instead, the seal was probably trying to rip the octopus' tentacle off with the force of the throw, she said in an email.

"I have seen seals doing this before, it's not an unusual sight but normally there isn't a person in the way," she wrote. "Often we see (seals) swallowing the tentacle at the surface like a large strand of spaghetti."

The seals often repeat the action multiple times, ripping off one tentacle at a time. Then Constantine believes the seals eat the rest of the body.

"It's a good meal, especially when they get a large octopus as shown in this footage," she wrote.

Morbid explanation aside, the video has prompted a lot of laughter, starting with Masuda and Mulinder.

"We instantly started laughing so (hard), we were talking about this all week," Masuda wrote to USA TODAY in an email.

He says the trip was a part of a launch event for the GoPro HERO7 camera. GoPro has shared the video on social media, where it's been viewed hundreds of thousands of times.