It was a page torn from a very old library book. Harry smoothed it out eagerly and Ron leaned close to read it too.

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 ven- omous 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.

'And to think all these years I thought a Basilisk was a lizard mating Jesus.' breathed Amelia.

And beneath this, a single word had been written, in a hand Harry recognised as Hermione's. Pipes.

It was as though somebody had just flicked a light on in his brain.

'Ron,' he breathed, 'this is it. This is the answer. The monster in the Chamber's a Basilisk – a giant serpent! That's why I've been hearing that voice all over the place, and nobody else has heard it. It's because I understand Parseltongue ...'

Harry looked up at the beds around him.

'The Basilisk kills people by looking at them. But no one's died – because no one looked it straight in the eye. Colin saw it through his camera. The Basilisk burned up all the film inside it, but Colin just got Petrified. Justin ... Justin must've seen the Basilisk through Nearly Headless Nick! Nick got the full blast of it, but he couldn't die again ... and Hermione and that Ravenclaw Prefect were found with a mirror next to them. Hermione had just realised the monster was a Basilisk. I bet you anything she warned the first person she met to look round corners with a mirror first! And that girl pulled out her mirror – and –'

Ron's jaw had dropped.

'And Mrs Norris?' he whispered eagerly.

Harry thought hard, picturing the scene on the night of Hallowe'en.

'The water ...' he said slowly, 'the flood from Moaning Myrtle's bathroom. I bet you Mrs Norris only saw the reflection ...'

'Herminoe, you bloody genius!' Amelia almost shouted, but Ron hushed her.