Once Lord Voldemort and Severus prepared the Mandrake Restorative Draught, the Basilisk, Herpo, was awakened.
Gilderoy Riddle, manipulating Lockhart’s shell, woke the Basilisk. By evening, it would begin moving through the pipes, randomly selecting some unfortunate young wizards to petrify.
Hogwarts fell into a state of panic for a time, and then The-Boy-Who-Lived stepped out.
Chapter 124