Chachong, or "tea pets" in English, are cute, charming, change color, and please the eyes or refresh the minds of tea drinkers. They are ornamental, but they bring life to any tea ceremony. Traditionally, the water used to warm up the tea set prior to drinking, the rinse from the leaves and any leftover tea are poured over the clay figurines.

The fluid's color and scent will change the tea pet's appearance and this characteristic has been brilliantly mastered by four students.

Their short video of a lychee-shaped "tea pet" has become an online hit. When hot water is poured on the dark brown object, it suddenly changes into a "fresh" lychee with red skin, green leaves and white meat.

The videos with the hashtag of "Color-changing lychee tea pet" have been viewed more than 3 million times on short video-sharing platform Douyin, and creative internet users have even come up with a way to make the color change last longer－by putting the tea pet into a glass teapot.

The lychee tea pet is actually the brainchild of four junior college students, Ye Zhiyuan, Guo Siqi, Zhou Zijun and Wang Huilin, who are all Cantonese.

Majoring in product design, they are studying at Huashang College Guangdong University of Finance and Economics, a private, independent college set up in 2004, in Zengcheng, Guangdong province.

The four were asked to design a product from scratch as part of a sixweek course in model design and production in December.

Guo says drinking tea is a cultural activity, so they decided to make a tea pet. Tea pets are actually small handicrafts stationed on the tea table, for either artistic appreciation or as cute toys to be doused with water, as people sit around with friends and socialize while sipping the brew.

Tea pets usually have auspicious meaning, such as fortune or good luck, the latter of which, as Guo notes, is illustrated by the lychee.

"Lychees are a calling card of Zengcheng, which are tasty and full, and as our college is based in Zengcheng, we wanted to honor the city in our design," Guo says.

Zengcheng is called the home of the lychee, a sweet, signature fruit from the Lingnan region that covers southern China.

Under the instruction of their tutor Zhang Zheng, the team drafted several shapes for the lychee after researching the fruit, from the pattern of its shell to the shape of the juicy fruit inside.

According to Ye, after finalizing their design on paper, they made a clay model.

"After making minor changes to the clay model, we finally arrived at our final product, which looks a bit more plump and vivid than real lychee fruit," Ye says.

"The material to make the tea pet is resin, and on the surface we use a macromolecule thermochromic material that will change color, when the temperature is higher," she explains.

"The longer hot water is poured over it and the hotter the water is, the longer time that material's color keeps changing."

According to Zhou, to take good care of the lychee tea pet, it needs to stay dry when not in use, and the owner should "nourish" it frequently with tea.

The course not only tasked them to design the product, but also produce and sell it.

The four took nearly a month searching for a factory to make their product, and finally found one after negotiations with more than 20 production companies across the country.

They produced 100 for the first batch, to give to friends and family.

The lychee tea pet received positive feedback when the team made their final presentation, which encouraged them to continue to make more for sale.

"None of us had marketing experience before, so we tried different ways, from setting up a stall to opening an online store on e-commerce platform Taobao," Zhou says.

They also hosted livestreaming shows introducing their work, which attracted more than 1,000 viewers. "But nobody bought the product, which frustrated us," Zhou recalls.

Their effort finally paid off when they started to make short videos of the process of the transformation the tea pet undergoes and upload them on various social media platforms. Since then, they have sold more than 20,000 tea pets.

Wang says now she and Zhou are responsible for managing the orders and packaging－the tea pets will be shipped to them from the factory, then they will re-examine each one with a water test before they send it to buyers.

The team applied for a patent in January. But there are already some similar lychee tea pet products sold online.

"It's not an easy path for original design products, but we want to continue with more attention on intellectual property. We hope the customers will like our products and support original designs by college students," Wang says.

Besides the lychee-themed ornament, the four are planning to design more tea pet products, as well as some cultural and creative items representing Lingnan culture.