 Fortunately for Harry and Ron , Hagrid left a set of instructions : to follow the spiders currently fleeing into the Forbidden Forest , which they do , only to find the monster blamed for the attacks fifty years before , a massive spider named Aragog , who explains to the duo that the real monster is one that spiders fear above all others . Hermione provides the last set of clues that inform them of the monster ’ s identity : It is a basilisk , which is a giant serpent ( hence Harry ’ s ability to understand it ) that kills with a stare ( although no one is dead because of various devices through which they indirectly saw the monster ) and which spiders ( such as Aragog and his offspring ) fear above all others . Harry figures out from hints Aragog dropped that a student who died during the previous attacks is Myrtle , and when Ginny is apparently taken by the monster into the Chamber , they discover that the entrance is in the bathroom they ’ ve been using to make Polyjuice Potion . Harry , Ron , and Lockhart enter the Chamber , but the dunderheaded professor ( who reveals that he ’ s a fraud ) causes a rockfall upon attempt to modify the boys ’ memories with Ron ’ s damaged wand , and Harry must enter alone . He arrives to find Ginny in a weakened state being watched over by a shadowy , ghostly Riddle , who explains that he is the boy who will become Voldemort in the future before setting the basilisk upon Harry ; Harry defeats the monster and destroys the diary , which makes Riddle disappear . 
