A basilisk was an immortal shaped like a tall, elegantly-featured lizard with slit-pupiled eyes in the front of its head, varied gray and white skin, and silver talons. It walked upright on its hind legs and often used one hand to carry its tail off the ground. Basilisks learned new languages very quickly, and were thus great travelers, as well as lovers of gossip.
Basilisks possessed a unique array of magical skills, including a sort of screech that could turn to stone any being within range. Basilisks were themselves stone-eaters, though they had expressed a preference for rare or aged stone, rather than that created by their own magic.