Myrtle's Bathroom is located on the second floor of Hogwarts, and was once used by female students, until Moaning Myrtle was killed by Tom Riddle, who set the Basilisk on her. It has been out of order ever since Myrtle began haunting the bathroom, and students avoid it. The sink with the snake-embossed tap is the entrance to the Chamber of Secrets, which is accessed by speaking the words "Open up" in Parseltongue. It was used by Tom Riddle to open the Chamber of Secrets, and by Harry Potter, Ron Weasley and Hermione Granger as a hiding place to brew Polyjuice Potion. Later, Harry Potter, Ron Weasley and Gilderoy Lockhart opened the Chamber of Secrets and it was accessed again by Ron Weasley and Hermione Granger to open the Chamber of Secrets and destroy Helga Hufflepuff's Cup with a Basilisk fang.