Doctors planned to operate yesterday to remove something unusual from a Peruvian toddler's belly—his twin. The partially formed fetus weighs over a pound and is nine inches long, according to Dr. Carlos Astocondor. The parasitic twin has no brain, lungs, or heart but utilizes the boy's blood supply The condition, know as fetus-in-fetu, occurs once in every 500,000 births. Though surgery to separate conjoined twins is daunting, the 12-member surgical team in this case was not expected to have serious difficulties, though the operation was to take several hours, reports ABC News. The 3-year-old boy, Isbac Pacunda, has suffered side effects from the unusual situation, including a distended belly.