Children like to put things in their mouths. That's what they do. Sometimes it's food, sometimes it's not. This is a story about the latter of the two.

What happened

Somehow, a four-year-old Saudi Arabian boy completely swallowed an entire bobby pin. After months of pain in his abdomen, his parents finally took him to the doctor where he admitted he ingested the pin. Doctors thought the pin would pass through the boy's system just like most other small objects would, but it didn't.

The boy eventually went in for an X-ray. The doctors found the pin ... but not where they thought they'd find it. It was actually stuck in the boy's kidney.

How did it get there? All we know is that the rounded plastic tips were digested, making the pin sharp enough to poke through the boy's bowel and get stuck in his kidney, where it then began to rust.

Dr. Yasmin Abdulaziz Yousef treated the boy and said it was a case unlike anything she'd ever seen. "We have treated a few patients with complications due to swallowed disk batteries as well, but I have never encountered a foreign object that perforates the bowel and gets lodged in the kidney in my practice before," she said.

Doctors were forced to operate on the boy. They removed the pin and he has reportedly recovered without further complications.

For parents

Learn from this. Take extra care to keep sharp or easy-to-swallow objects out of reach of small children. Babies explore the world with their mouths very early on in their development. It's a normal phase called mouthing. It's hard to stop a child from putting things in their mouth, but you can control what objects your child has access to.

A good rule of thumb is to determine whether a potentially chewable object can fit through a toilet paper roll. If it can, chances are it can be swallowed too.