Dolls are no longer exclusively for children. Jiang Fan, a 22-year-old college graduate in Shanghai, became captivated by Molly dolls two years ago. Now, she has a collection of more than 70, and the number is climbing.

These tiny toys, commonly known as blind box figures, come in sealed packaging and collectors have no idea which specific figure from a series they are buying. Many series even feature rare special figures or lucky-draw figures.

"It's kind of like buying trading cards, except you don't get a piece of cardboard, you get a cool toy," Jiang said. "The sense of uncertainty intrigues me!"

Molly dolls are little dolls with curly yellow hair, big turquoise eyes and pouting lips. Each one costs 59 yuan ($8.5), which means Jiang has to pay at least 708 yuan for an entire series of 12 figures. "My purse really hurts," she joked.

Jiang is not the only "big kid "who is fascinated with the dolls. In April this year, the biennial Shanghai Toy Show attracted more than 100,000 fans of designer toys, just like Jiang.

The sponsor of the toy expo is Pop Mart, a leading designer toy company in China. Founded in 2010, the company sells eight categories of lifestyle commodities. But it put an emphasis on designer toys in 2017, after the company detected the enormous potential of the new market and launched Molly, due to the global popularity of Sonny Angel, another famous designer toy brand.

The company sold about 4 million Molly dolls in 2018 and expects to replicate the sales volume this year, Wang Ning, founder of Pop Mart, said in a speech at the China Central Academy of Fine Arts in April.

Dividends are staggering. The annual net profit of Pop Mart in 2017 was approximately 8 million yuan, and it reached 21 million yuan in the first half of 2018, jumping 14 times compared with a year ago, according to the company's half-year report.

Most of Pop Mart's customers are aged between 18 and 35, and are students and white-collar workers, according to Guo Xiao, chief marketing officer of the company.

"Young people today are better educated and capable of earning more money," explained Guo. "That's why they crave novel and high-quality products."

However, that is not the only reason young people have taken a fancy to Molly dolls rather than other toys.

The main purchasing forces of the designer toy market, the post-1990 and post-2000 generations, were born in an age of entertainment and are constantly distracted by new products, making it hard for any hit TV series, film or star to become a phenomenon.

"What makes intellectual property successful? I think it's time," said Wang. "With a faster pace of life and fragmented time, we can't afford to hatch a popular product. But a Molly player doesn't have to spend weeks watching a TV series. Basically, displaying the dolls on a desk is enough."

Change in value is the other main factor, according to Wang.

"People used to reach consensus on the preference of figures; however, today, everyone's favorite figure is different," he said.

In fact, the thriving designer toy in a blind box epitomizes the entire toy market for adults. More and more youngsters across the world are changing their tastes and taking up collecting designer toys and model toys. According to the 2019 Global Toy Market Report made by the US Toy Association, customers aged from 18 to 34 make up half of the people in the United States who buy toys for themselves.

In China, the performance of toys for adults is also remarkable. Statistics from China Customs indicate that the import volume of components of model toys increased by 49.8 percent year-on-year in 2017, and the turnover soared by 95.6 percent during the same period.

Tang Yiping contributed to this story.