Hvaldimir was a hit from the first time he was spotted in the wild, off the coast of Norway in April 2019.
He was wearing a harness that looked like it had a small camera mount and was marked with the words "Equipment St Petersburg" in Russian.
What's more, he was far friendlier than most beluga whales and seemed very comfortable around humans.
So began the speculation that he was a "spy whale", with some marine researchers pointing to previous cases where the Russian navy was believed to have trained whales and dolphins.
From the speculation came the whale's nickname, crowd-sourced by a Norwegian broadcaster.
"Hvaldimir" is a combination of the Norwegian word for "whale" and the first name of Russian President Vladimir Putin.
Moscow has never shed light on Hvaldimir's past, though it's generally accepted that the whale must have previously been held in some kind of captivity.
If he was a "spy whale", however, his cover was well and truly blown.
For the next few years, he'd travel the waters of the Norwegian coast, delighting people with his friendly antics playing football, cheekily harassing seagulls, and even rescuing phones that fell into the water.
Regina Haug was a documentary filmmaker when she went to meet Hvaldimir in 2019.
"I just went to film Hvaldimir for a week because I was curious about it, there's not any good information about this whale … it was only a few joke-type news stories."
She vividly remembers the moment they met.
"I was with people who had been hand-feeding him and they believed he could only eat food out [of peoples'] hand, and he'd been gone for a few days and they were worried he hadn't eaten.
"And in my mind, I thought, 'Maybe he's taught himself to eat.'
"Sure enough, he's swimming towards us … and he goes down into the water and comes back up and hands a huge fish to me that he had caught.
"And he hands me this fish, and looks right at me, and it's almost like he was telling me and everyone in the boat, 'Look what I can do!'"
The dangers of being an internet sensation
Hvaldimir amassed a worldwide following, but the attention wasn't always a good thing.
The whale's popularity meant he became something of a tourist attraction, and his unusual proximity to people meant he was at greater risk of injury.
Ms Haug said, from the first time she met him, she was concerned for his safety.
"I was like 'my God, this is not going to end well' and I had people that very week telling me he's either going to die by a propeller strike, a boat strike, drown in a fishing net or someone is going to take his life on purpose."
Ms Haug went on to create the non-profit organisation OneWhale, which is described as a "public safety program" for Hvaldimir.
She says the team documented extensive injuries the whale suffered.
"We have watched him get hit by propellers, his body sliced open by sharp objects, injuries from tourists putting sharp things in his mouth."
Ms Haug and OneWhale also advocated for Hvaldimir to be relocated further offshore, in an area with less traffic where he might join a nearby pod of belugas.
By the time he died, OneWhale had secured permission from the Norwegian government and was organising and fundraising for his relocation.
But there were those who opposed the plan.
The conflict over a whale's best interests
After the application to relocate Hvaldimir was granted, more than 70 marine experts signed an open letter to Norway's government warning against the idea.
Signatories included former members of OneWhale, who had split from the organisation over differing opinions on the best way to protect the beluga.
One such person was former OneWhale member and marine scientist Sebastian Strand, who founded Marine Mind, another organisation that had been monitoring Hvaldimir but opposed his proposed relocation.
In August, Mr Strand told Yahoo News, "We fear the consequences of transport and the uncertain events that would occur."
Arguments against the relocation included concerns the whale would have a hard time acclimatising to a new area; that a proposed relocation site would be too close to Russia where he would run the risk of being recaptured; that it would be too hard to monitor him and that he wouldn't be able to catch enough fish to feed himself.
Hvaldimir's death
Hvaldimir was reported to have been found dead in a bay in Southern Norway on Saturday.
A necropsy is underway to determine the cause of death.
Ms Haug said seeing Hvaldimir's body was "our worst fears basically coming true".
"We're not going to speculate right at this moment, but we feel very strongly we know how he was killed," she said.
"It's the things that we had been warning about for five years, about his very high-risk life in Norway.
"It was a matter of time that something like this would have happened," said Vanessa Pirotta, an Australian marine scientist who has focused on the interactions between humans and whales.
Despite the differing opinions on how best to protect Hvaldimir, his presence and popularity carried with it a tremendous message about conservation.
"Due to [his] close proximity to human activity [he] has represented some of the challenges that whales globally around the world face," Dr Pirotta said.
"He's a huge success story that animals can come out of captivity and make it again in the wild," Ms Haug said.
She hopes that Hvaldimir's story, including his death, will lead to better protections for other animals.
"Maybe it will be the next walrus who comes into busy cities, and instead of being killed she or he will be moved to a better location, or maybe it will be Bella, the beluga in Korea who's living in a glass box in the middle of a shopping mall, maybe Bella will be released.
"What I would want for everybody out there is to remember how special he was so that they can bring that forward into their life when they're dealing with any animal in need."
