This article is about the creature. For the moment, see The Basilisk.
A basilisk is a legendary creature, a snake hatched from a chicken egg by a toad. It is capable for living for hundreds of years and is the monster dwelling in the Chamber of Secrets.
From the Story
Book 2, Chapter 16; "The Chamber of Secrets"
"The Basilisk is an enormous snake sometimes referred to as the King of Serpents. It is born from a chicken’s egg that is hatched beneath a toad; its fangs are poisonous and its stare is lethal. The crowing of a rooster is fatal to it. The Basilisk is the creature from the Chamber of Secrets that has been attacking students."
Book 2, Chapter 17; "The Heir of Slytherin"
"The Basilisk emerges from the mouth of the statue of Salazar Slytherin in the Chamber of Secrets. Tom Riddle speaks in Parseltongue and orders the Basilisk to kill Harry. The serpent makes its way towards Harry but Fawkes the phoenix gouges out its eyes so that it can no longer kill Harry by looking at him. Eventually Harry drives a sword into the roof of the Basilisk's mouth and kills it, but not before one of its fangs pierces Harry's arm above the elbow."
"Of the many fearsome beasts and monsters that roam our land, there is none more curious or more deadly than the Basilisk, known also as the King of Serpents. This snake, which may reach gigantic size, and live many hundreds of years, is born from a chicken’s egg, hatched beneath a toad. Its methods of killing are most wondrous, for 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."