NEW YORK (Reuters) - Despite the bone through his nose, his shaved head and pierced face, the 25-year-old pacing a seedy stretch of New York sidewalk admitted he was terrified of what he was about to do. But after a few minutes, a couple cigarettes and several deep breaths, he sat in the basement of a storefront tattoo parlor, closed his eyes and let a friend split his tongue down the middle with a scalpel. The latest trend among teens and 20-somethings who indulge in so-called extreme body modification, forking one's tongue like a serpent's "is an art form," said...