Megalania prisca was a large, prehistoric lizard that lived in Australia during the Pleistocene epoch, around 1.6 million to 46,000 years ago. It is believed to have been one of the largest terrestrial lizards, reaching lengths of up to 7 meters (23 feet). This giant monitor lizard was a carnivore, preying on various animals, including large mammals. Fossil evidence suggests that Megalania had powerful limbs and a robust body, allowing it to be an effective predator. Its extinction is thought to be linked to climate change and the arrival of humans in Australia, which may have impacted its habitat and food sources.