A giant, 23-tonne humpback whale took it upon itself to push an unsuspecting snorkeller through the water off the Cook Islands, looking to protect her from a nearby shark.
Stunning video and images show how the whale pushed whale biologist Nan Hauser with his head and his mouth, tucked her under its pectoral fin, and even lifted the biologist out of the water on one occasion.
Ms Hauser, 63, said the moment is perhaps proof of whale's intuitive nature to protect other species of animal - including humans - something she believes has never been captured on film. She also believes it is proof of the whale's intuition, a feeling she compared to firemen being willing to rush into a house on fire to help save the lives of those they do not know.
Lurking near the enormous mammal and Ms Hauser was a 4.5 metre tiger shark and though the animal is only visible in the distance in the footage, her team also filmed the diver from aboard a nearby boat, capturing her coming to the surface and shouting that there was a shark nearby.
Out of shot, another whale was persistently tail slapping and keeping the shark away from Ms Hauser and the whale that was pushing her.
When Ms Hauser saw the shark she initially thought that it was another whale - until she noticed its tail moving from side to side, like a shark, instead of up and down, like a whale.
As she returned to the safety of the boat in the waters off Muri Beach, Rarotonga in October, the whale even surfaced to check on her.
Ms Hauser, who lives on the Cook Islands, said: "I wasn't sure what the whale was up to when he approached me, and it didn't stop pushing me around for over ten minutes. It seemed like hours. I was a bit bruised up.
"I've spent 28 years underwater with whales, and have never had a whale so tactile and so insistent on putting me on his head, or belly, or back, or, most of all, trying to tuck me under his huge pectoral fin.
"I tried to get away from him for fear that if he rammed me too hard, or hit me with his flippers or tail, that would break my bones and rupture my organs. If he held me under his pectoral fin, I would have drowned."
"I didn't want to panic, because I knew that he would pick up on my fear.
"I stayed calm to a point but was sure that it was most likely going to be a deadly encounter.
"I feel a very close kinship with animals, so despite my trepidation, I tried to stay calm and figure out how to get away from him.
"I never took my eyes off him which is why I didn't see the shark right away."
Though the footage shows the whale biologist making contact with the giant mammal, touching these animals is something that Ms Hauser is very strict about never encouraging; the whale was the one forcefully making direct contact with her, she said.
Ms Hauser added: "I never touch the whales that I study unless they are sick or stranded on the beach.
"In my head, I was a bit amused since I write Rules and Regulations about whale harassment - and here I was being harassed by a whale"
Ms Hauser had never seen the whale before she entered the water that day, and the biologist believed at the time that the whale's actions meant that it was trying to tell her something. "
The cameraman who filmed the encounter nearby had never filmed whales before, either, so was unaware of just how unique this behaviour was.
On Ms Hauser's nearby research vessel, however, her team was concerned for her safety. They abandoned their drone footage because, as she describes the moment, they "did not want to film my death."
Ms Hauser had heard of the altruistic behavior of humpback whales before - protecting their young, other species of whales, seals, and dolphins - but scientists have never seen humpbacks actually protecting humans.
Dolphins have been known to exhibit protective behavior and many stories have been told.
Ms Hauser had never experienced such an event in person with a humpback, or seen footage in the past 28 years of studying whales.
For over ten minutes she was focused on the whale, unaware of the shark nearby.
The biologist now hopes to share the footage that she and her team were able to capture, in order to expand research and awareness of such actions from whales.
Humpbacks are known for protecting other species of animals. They hide seals under their pectoral fins to protect them from killer whales.
"They truly display altruism - sometimes at the risk of losing their own lives," Ms Hauser said.
But this is the first documented case where a humpback whale has protected a human from a huge tiger shark.
"Other fishermen and divers have seen this same shark nearby the reef and say that it is as big as a pickup truck.
"Some say that it is 20 feet long.
"It's funny how the tables are turned here: I've spent the past 28 years protecting whales, and in the moment, I didn't even realize that they were protecting me!" Ms Hauser said.