When Kim Min-seok gave the go-ahead in June 2016 to publish a 90-second clip of a children's song, he had no idea what he was unleashing.
It became a global phenomenon, clocking up more than 16 billion views - YouTube's most watched video ever.
That song was the incredibly catchy Baby Shark.
Not only has it captivated toddlers and terrorised adults around the world, it laid the foundations for its creator Pinkfong to become a media business worth hundreds of millions of dollars.
“We didn’t expect it to stand out from our other content," said Mr Kim, Pinkfong's chief executive, told the BBC from the firm's headquarters in Seoul.
On Tuesday, that journey took Pinkfong to the South Korean stock market, where its shares rose by more than 9% on their debut, giving it a valuation of more than $400m (£304m).
'We didn't expect a salary'
Founded in 2010 as SmartStudy, the firm made digital content for children up to 12 years of age. It had just three employees, including Mr Kim and the firm's chief technology officer, Dongwoo Son. The office was tiny - even smaller than this," recalled Mr Kim, gesturing to the conference room he was calling from.
Pinkfong went through several major overhauls, including shifting its focus to toddlers. The firm grew to around 100 employees and prioritised simpler, learning-based games and content. And that's when Baby Shark emerged, Mr Kim said. It now has around 340 employees, with offices in Tokyo, Shanghai and Los Angeles.
The Baby Shark moment
Baby Shark is believed to have originated in the US in the 1970s and was often sung at children's summer camps. The song, which repeats the phrase Baby shark, doo, doo, doo, doo, doo, doo is attractive for children, though possibly annoying for adults, said media analyst Kevin Chew from the Nanyang Technological University.
But it was an instant hit and only gained traction when its dance routine was featured at children's events in South East Asia. Videos of children and adults dancing to the song started to spread online and the clip went viral. In November 2020, the Baby Shark clip claimed the title of YouTube's most viewed.
One-hit wonder?
Pinkfong's other franchises like Bebefinn and Sealook are growing fast but the firm must prove its success is not just reliant on Baby Shark. The company's target audience is a major plus as toddlers tend to watch the same material repeatedly. Meanwhile, Bebefinn has leapt ahead, generating roughly 40% of the firm's earnings.
It raised almost $52m in its stock market debut and plans to use the money to expand its line-up of films and characters, said Mr Kim. The company also aims to become a tech-driven content creator, using viewing patterns and other data to shape its new projects.
