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.
“But looking back, it became a major turning point that set the stage for our global journey.”
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).
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. Pinkfong went through several major overhauls, including shifting its focus to toddlers.
Baby Shark, which originated in the US in the 1970s, gained traction when its dance routine was featured at children's events in Southeast Asia.
Videos of children dancing to the song went viral, leading Pinkfong to achieve substantial revenue growth.
However, Pinkfong faces the challenge of proving its success isn't solely reliant on Baby Shark, even as other franchises like Bebefinn begin to flourish.
Kim Min-seok insists there are plans to expand Pinkfong's lineup and tackle the growing market using data-driven content creation strategies.
