Deinocheirus has been a mystery to paleontologists for decades since the discovery of a pair of giant fossil arms in the Gobi Desert. For the longest time, they were the only clue to what sort of creature it could possibly be. This led paleoartists and researchers alike to make some very interesting guesses over the years. Was it a giant tyrannosaur or other theropod? What about a ground sloth? Maybe a giant Deinonychus?! Imaginations ran wild until more material was discovered, and we really weren't ready for the mega goose that we got.