Enigmosaurus (meaning "Riddle Lizard") is a genus of therizinosauroid theropod dinosaur from the Late Cretaceous of Mongolia, central Asia. It is a herbivorous bipedal dinosaur. The holotype, IGM 100/84, was collected in the Bayan Shireh Formation (=Baynshirenskaya) in Khara Khutul, southeastern Mongolia, dating from the Cenomanian and the Turonian stages, around 98-89.8 million years ago. It was first reported in 1979. It consists of a partial skeleton, lacking the skull, which includes a nearly complete pelvis with part of the right ischium missing.