Gorgonopsids were a group of prehistoric reptiles that lived during the late Permian period, around 260 million years ago. They are part of the larger group known as therapsids, which are ancestors of modern mammals. Gorgonopsids were characterized by their large skulls, sharp teeth, and powerful jaws, making them effective predators of their time. These creatures varied in size, with some reaching lengths of up to 3 meters (10 feet). Gorgonopsids had a unique combination of reptilian and mammalian features, such as a more advanced jaw structure. Their extinction occurred during the Permian-Triassic extinction event, which wiped out many species on Earth.