". . . aside from its deadly and venomous fangs, the Basilisk has a murderous stare, and all who are fixed with the beam of its eye shall suffer instant death. Spiders flee before the Basilisk, for it is their mortal enemy, and the Basilisk flees only from the crowing of the rooster, which is fatal to it." (CS16)
A wizard-bred Dark creature of enormous power, this extremely poisonous giant serpent (up to 50 feet in length) is brilliant green in color with long thin saber-like fangs and bulbous yellow eyes. The first basilisk was created by Herpo the Foul thousands of years ago (FW).
A basilisk can live for at least 900 years given an adequate food supply, and as it can eat most vertebrates (including humans), this is not difficult to achieve. The male can be distinguished from the female by the scarlet plume on its head, but basilisks are usually magically rather than normally bred.
Basilisk-breeding has been outlawed since medieval times and in the present day falls under the Ban on Experimental Breeding, but this law has rarely been broken even by Dark wizards, since only a Parselmouth can control a basilisk.
When unleashed by the Heir of Slytherin using Parseltongue, the basilisk that lived in the Chamber of Secrets searched the castle for its prey, Muggle-born students, which it apparently could identify by smelling their blood (“I smell blood…” the creature cried as it wandered the pipes). When its eyes were pecked out by Fawkes, it attacked Harry using its keen sense of smell. Harry killed the basilisk by thrusting a sword through the roof of its mouth. Harry’s arm was pierced by one of the basilisk’s fangs, the poison of which nearly killed him.
Apart from its specific magical powers and long lifespan, many of the characteristics of the basilisk follow naturally from it’s being a serpent (see). Like more mundane serpents, the basilisk sheds its skin at intervals, and its varied diet is typical of the larger snakes, which tend to pursue larger and larger prey according to their own size and capabilities. It’s quite possible that had Harry both retained his wand and been more experienced in Defence Against the Dark Arts, he might have lost his battle against the basilisk in attempting to use Stunning Spells; although not explicitly stated, the basilisk’s skin probably has the same armor characteristics as dragon skin, leaving its eyes and the inside of its mouth as its only vulnerable points.
- The Basilisk in the Chamber of Secrets could only be controlled by Salazar Slytherin "or his descendants," including the Gaunt family, most of whom were Parselmouths (Pm).
- The Sword of Gryffindor was "impregnated with basilisk venom," which is why it could destroy Horcruxes (DH15).
- Harry got a well-deserved laugh when he heard over the Wizarding Wireless that people thought Voldemort could petrify them with a glance like the Basilisk (DH22).
"basilisk" Eng. in the legendary sense means this creature, but also comes from L. "basilicus" royal, so the nickname "King of Serpents" is particularly apt. The detail about males being crested appears to come from the real-life basilisk, which is a kind of iguana.
The basilisk is a creature from Greek and Roman legends, described variously as a snake, a snake-rooster hybrid, or even a cow-like creature. A common aspect of the stories is that the basilisk can kill with a glance or with a single breath. While the legendary basilisk is said to be defeated only by a weasel (which would be thrown into the hole where the basilisk lives), Rowling's version is defeated by roosters.