We've all heard of triplets, quintuplets, sextuplets, and so on. But have you ever heard of a twin inside it's twin?
Fetus in fetu is a rarely occurring condition that results when a fetus surrounds and encapsulates it's twin during development in the uterus. Sometimes the encapsulated twin is absorbed, but on rare occassions it can continue to live and grow inside the larger fetus, sometimes for decades. A 36 year old man in India was rushed to a hospital after his abdomen became so swollen that he looked like he was 9 months pregnant. Doctors suspected a tumor, but were surprised to find a partially formed human inside the man's stomach, including hair, genitalia, arms, legs, and a variety of bones.