That's what Li Fu, a Chinese man in Yunnan province found out when he visited the doctor complaining of splitting headaches: There was a broken-off 4-inch knife blade (now clearly rusted) in his skull (video below).
Though it may seem unbelievable that he never noticed, and miraculous that he didn't die from the injury, this sort of thing has been known to happen before. A few years back, construction worker Patrick Lawler went to the dentist complaining of toothache and learned that he'd accidentally fired a 4-inch nail through the roof of his mouth nearly a week earlier, barely missing an eye.
These, at least, were unintentional incidents. Then there was Chris Foster of Britain, who swallowed his keys one night while drunk, allegedly to keep his friends from taking him home.
It worked out for Foster, who just waited for the key to come out the other end, but it's best to keep in mind, Jeannine Stein has pointed out, that swallowing foreign objects isn't cheap.
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