Doctors in China had to perform emergency surgery on a two-year-old boy who they discovered was carrying his twin brother INSIDE HIS STOMACH.

According to The Inquisitr, the boy, named Xiao Feng, had been suffering from breathing difficulties and his stomach was extremely swollen before he was admitted to the hospital to undergo an operation to “give birth” to his twin.

Following X-rays and MRI scans, doctors at the hospital confirmed that Feng was in fact carrying the undeveloped fetus of his twin inside his stomach. He was rushed to the operating room for emergency surgery to remove it.

The case known as cryptodidymus, or conjoined twins, is extremely rare, if not unprecedented in the world of medicine. The unborn fetus measured around 10 inches in width and was fully formed in terms of its spine and limbs.

Normal twins are formed when an egg splits after fertilization, however, when the egg itself fails to fully separated, that’s when conjoined twins are formed

Doctors noted that it’s a good thing the boy was admitted to the hospital when he was, because if left untreated, the dead parasitic twin inside of him — which was taking up about two-thirds of his stomach — would have basically rotted away and eventually led to his death.