This time last year, two teams of paleontologists announced that they had finally solved one of the most inscrutable mysteries in the history of life on Earth. The Tully Monster - a flat, bug-eyed, nozzle-nosed animal truly worthy of the title Monster - went from a 300 million year old Rorsarch test to a vertebrate, a strange lamprey rather than a pincer-faced invertebrate. Fossil fans sent up a cheer as the unusual critter was welcomed into the fold. But now a different group of researchers has once again raised uncertainty about what, exactly, the Tully Monster is. Read more