An 8-year-old had a "parasitic twin" growing out of his chest.

Deepak Kumar Paswaan (nicknamed "Octoboy") had the arms and legs of an undeveloped twin growing out of his chest. The twin stopped developing in the womb before fully separating from Paswaan before he was born. The boy had to spend the first 8 years of his life like that until he could have an operation to get the additional appendages removed. While some people thought that his unusual condition was something holy worthy of reverence, others believed he was a monster. Some people have even thrown stones at the child.

In a recent television special, doctors in Bangalore, India separated Deepak from his undeveloped conjoined twin surgically. He and his family publicly appealed for the money for the surgery back in February of last year, and he was finally able to have the operation in June.
(Sources: 1, 2)