Adasaurus (/ˌɑːdəˈsɔːrəs/ AH-də-SAWR-əs; "Ada's lizard") is a dromaeosaurid theropod dinosaur from the Late Cretaceous Period of Central Asia. It was a small bipedal carnivore with a sickle-shaped claw on the second toe of each hind foot, and was perhaps 1.8 m (5.9 ft) long. The genus name Adasaurus is taken from Ada, an evil spirit in the mythology of Mongolia, and the Greek word sauros meaning 'lizard'. The species name, for the single species, (A. mongoliensis), refers to the country of origin. Adasaurus was named and described in 1983 by Mongolian paleontologist Rinchen Barsbold.