The newest craze young kids are taking part in at school could potentially leave them in hospital, according to experts. A doctor has issued a warning to parents who might not realise how harmful the seemingly innocent game could be. Here’s everything you need to know. The magnetic ball craze The new trend involves youngsters using small magnetic balls to make it look like they have facial piercings. They’ll put one inside their mouth and the other on the outside so that the magnets clamp together to mimic the effect of a lip or a tongue piercing, for example. However, this poses a very serious threat to the digestive system if the small magnets get swallowed. Warning to parents A letter from a doctor based in Stockport has been circulating primary schools, issuing a warning to parents not to buy the magnets for their children. In the letter, the doctor said, “I cannot emphasise enough how dangerous these can be if swallowed. “You may wonder why a child would swallow these or you may think ‘my child wouldn’t swallow them’ but I plead with you not to take the risk.” The letter went on to describe how some children were putting numerous small magnetic balls together to stick to the outside of their face. “They then use their tongue to move the larger ball in their mouth to make the balls on their face move, which understandably kids find amusing,” the letter continued. “However, some of the individual balls in their mouth can come away and be accidentally swallowed. The balls are highly magnetic and when swallowed can cause severe damage to the digestive tract.” Abdominal surgery The doctor explained that as the magnets move through the child's digestive system, they can magnetise together, even when in different parts of the bowel. “The pressure applied to the bowel tissue lying between the two magnets is so strong it causes a perforation in the bowel,” the doctor’s letter warned. “This is extremely serious and can be fatal if not identified and promptly fixed by abdominal surgery.” “There has been a case locally in which a young child needed abdominal surgery and within Stockport. I am aware of at least three cases. Please do not buy these for your children and if you already have them, consider removing them,” the letter ended.