A giant lizard, as its name implied, was a massive variety of Lizard, growing around 15 feet long. They were quick at traversing land, and could climb as fast as they crawled. Many of these beasts also were semi-amphibious, being able to retain their breath for a long period of time, and could climb upside down on ceilings and difficult surfaces. Somewhat lazy hunters due to their reptilian temperament and solitary nature, giant lizards often simply opted to attack and eat any creature in their way.
They were popular pets and mounts among Troglodytes, Dark Elfs, and Lizardfolk, preferring to lurk in swamps, caves, and marshes. Some variants of giant lizards native to the Underdark could grow to nearly 25 feet in size, and often possessed too fierce a temperament to be subservient to Mortalkind.