Synonymous with Urban Myth or Legend: A widely circulated story, often believed to be true by the teller, but usually distorted, exaggerated or fabricated for sensational effect, and often having elements of humour or horror. Wiktionary
He: "Whoa...check out this YouTube video of Lady Gaga at Glastonbury showing a little 'something extra' peeking out from under her miniskirt during her performance. She's even 'fessed up that it was just a little bit of her penis because she is a medically certified hermaphrodite."
She: Well she's definitely not a man. Come on, not only is it clearly absolute bollocks, but also it definitely sounds like a classic beat up of urban fictionary.