1 / 9The curious youngster, from Dongguan in South China, needed surgery on his bladder to remove the magnet toys, called Buckyballs.2 / 9He'd suffered a range of symptoms, including blood in his urine, but was too afraid to tell his mum and dad.It was only when the parents took the boy for a check-up at a local hospital they discovered what had happened, according to Dr Li Honghui, chief urologist at Dongguan Children's Hospital.3 / 9Medics discovered a string of 20 magnetic balls in his bladder.Dr Li performed a cystoscopy - an endoscopy of the bladder - and was able to count the rusted magnets.4 / 9He said: 'We couldn't remove a string of 20 spheres through a cystoscopy, so we opted for a minimally invasive surgery instead.'The child's urethra was too narrow to remove the Buckyballs without risking further injury, but doctor carried out an operation that day.5 / 9Dr Li said: 'Children are very curious about their body as they grow.'In terms of inserting objects in the urethra, we found the phenomenon in boys of two age groups - five to six, and 10 to 13.'6 / 9Children may be too scared to tell family members, so parents have been advised to seek medical attention for their kids if they notice symptoms including frequent urination, pain during urination, or blood in the urine, he said.7 / 9Earlier this year, a 13-year-old schoolboy had to have 29 magnetic balls removed from his bladder - three months after stuffing them up his penis.8 / 9The boy’s parents eventually took him to the hospital when they noticed him walking with a limp.9 / 9Dr Yanyan revealed that the young lad believed he could pee the metal balls out of his body.