Enormous tape worm
You know what they say about raw beef: You shouldn't eat it (at least, not unless you cook it first). A man in China learned this lesson the hard way after finding out that he had a 20-foot-long (6 meters) tapeworm living inside of him— a result of chowing down on uncooked cow meat. The tapeworm likely lived inside the man's small intestine for at least two years before he went to see the doctors who would ultimately help him flush out this lengthy stowaway. [Here's a list of top meats that can make you sick.] The man complained of stomach pain, vomiting, loss of appetite and weight loss; his doctors were able to quickly identify the cause of these symptoms because the patient brought along a crucial piece of evidence — a fragment of the parasite, which he had found in his stool. Combined with the patient's known predilection for raw beef, the tapeworm specimen helped doctors guess that the man was sharing his intestine with Taenia saginata(a species of beef tapeworm). After being treated with an antibiotic that caused him to pass the tapeworm out of his body within hours, the man's symptoms cleared up in just three months, according to a case report published in The New England Journal of Medicine in January 2016. Presumably, the man's preference for uncooked beef passed just as quickly.