If the band X were twin brother and sister, we'd be living in some sort of alternate reality, an alternate reality where Roadsie Prophets wasn't filmed, a world where John Doe didn't make that lame guest appearance on One Tree Hill, unfortunately, this is not the case. But if there were a twin brother and sister combo who sounded like X, it would be Vena Cava, not to be confused with the 6 lame ass metal bands named Vena Cava. This Vena Cava is a unicorn, except they don't have a horn growing out the top of their head, and they actually exist.