Slytherin Dungeon

The Slytherin Dungeon is located behind a wall in the cellars of Hogwarts School of Witchcraft and Wizardry. A password spoken to the wall is required to enter it; whereupon a passage is revealed leading to the common room -- a low-ceilinged, dungeon-like room with greenish lamps and chairs. This dungeon extends partway under the lake (which is why it has green-coloured lamps).

In Harry's second year he and Ron went into the Slytherin common room disguised as Crabbe and Goyle with the aid of Polyjuice Potion to attempt to discover the identity of the Heir of Slytherin. The entry password was Pure-blood when Draco Malfoy let them in. The Polyjuice Potion's wearing off prompted Harry and Ron to leave after staying nearly an hour, still not finding out the identity of the Heir of Slytherin.

In 1998, Harry, operating under the alias "Vernon Dudley," attempted to defend his false claim that he was a member of the Slytherin house by describing the location of the Dungeon to the Snatchers.

Appearances

 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Chamber of Secrets (film)
 * Harry Potter and the Chamber of Secrets (video game)
 * Harry Potter and the Order of the Phoenix (video game)
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Deathly Hallows