The House Key is a key that Heather Mason uses in Silent Hill 3. It is automatically found in Heather's inventory following her nightmare and is used to unlock the door to her home in Daisy Villa Apartments.
After completing her excursions through the Otherworld Hilltop Center, Heather makes her way into the apartments nearby. Her home is in Room 102, and after using the key, Heather quickly enters and greets her father, trying to tell him of the "crazy" things that have transpired.
- Main article: UFO Ending#Silent Hill 3
The House Key can also be used to unlock the game's secret UFO Ending. After defeating a minimum of 30 enemies using the Heather/Sexy Beam, the ending will automatically play after opening the door to Room 102. In the following scene, Heather relates to her father the strange events that have taken place, and with the help of aliens, Harry proceeds to exact his revenge and destroy Silent Hill.