Later, Harry and Ron visit a still-petrified Hermione in the hospital and notice that she happens to have a crumpled piece of paper in her hand. Hmm…
The paper has a description of a monster called a basilisk. Based on the info on this page, Harry is guessing that this is creature in the Chamber of Secrets. It's a type of snake so that explains why only Harry can hear it. Spiders hate it and it kills people by looking it in the eye.
Yeah, but no one is dead. Why is that?
Harry guesses that's because no one looked the basilisk right in the eyes. Mrs. Norris must have seen it in the reflection of the water on the floor. Colin saw it through his camera lens. Justin saw it through the ghost of Sir Nicholas. And Hermione saw it in the mirror. Genius.
But how's the snake getting around the castle? Hermione's luckily left a little note about that on the paper in her hand. It's been going through the pipes.
Then Harry thinks of the dead girl in the bathroom from fifty years ago—could that be Moaning Myrtle?
Just then, Ron and Harry hear Professor McGonagall announcing that all students should head to their dorms. Naturally, Harry and Ron head towards the place the teachers are gathering.
Turns out, a student has been taken by the monster. It's Ginny Weasley. And someone has written a message in blood on the wall—"Her skeleton will lie in the chamber forever."