What people love most about milk tea boba, otherwise known as bubble tea, are the chewy and sweet tapioca balls sitting at the bottom of the drink. These delicious balls are usually made out of tapioca starch and brown sugar, but as one Chinese reporter recently found out, sometimes they're made out of something else.

A local reporter for Shangdong Television in Qingdao, China got a little thirsty while on the job just a while ago, so he ordered a milk tea boba from a local shop. A few hours after drinking the tea and munching on all the tapioca balls, he fell quite ill, so he went to the hospital for a check-up. After a number of tests, and with no answer as to what was causing his patient's distress, the doctor performed a CT scan and saw some undigested tapioca balls sitting at the bottom of the reporter's stomach. So the doctor extracted the balls and sent them to Qingdao University’s Chemical Experimentation Center, where scientists analyzed them to figure out what exactly these things were made of.

When the scientists reported back to the doctor that the tapioca balls were "highly adhesive," the doctor immediately relayed this information to his patient. And because he was a reporter, the man who had ingested these mysterious materials decided to do some investigating. What he found out while going undercover at the tea shop was something he had trouble digesting — literally. The tapioca balls that he so happily chewed on and swallowed a few weeks earlier were actually produced in a chemical plant and made out of the soles of leather shoes and tires. And yes, the shoes and tires were not new when they were recycled. Gross!

So if you ever go to Qingdao, you might want to make sure that the tapioca balls sitting at the bottom of your tea are actually made of something edible.