Thanos, named after the Marvel Comics character, is a genus of carnivorous brachyrostran abelisaurid dinosaur that inhabited Brazil during the Santonian stage of the late Cretaceous Period. It consists of a single species, known as T. simonattoi. Thanos is estimated to have measured around 5.5–6.5 meters (18.0–21.3 feet) in length.

Despite the incompleteness of the fossil material, several distinctive characteristics are discernible. These include a well-developed keel that widens and deepens towards the posterior section of the ventral surface, two small foramina on each lateral surface of the centrum separated by a relatively broad wall, and pronounced and deep prezygapophyseal spinodiapophyseal fossae. Based on these features, Thanos may have possessed more advanced traits compared to other abelisaurids of its time.