The Santas Grotto is a for your pet's house that is unlocked by building the collaborative object the Santas Grotto mail-drop. This room was added to the game on 23 December, 2011. It is one of the few secret rooms that does not cost Playfish Cash. Like all secret rooms, you can only have one room of this type; building multiple Santas Grottos will not get you additional rooms. Selling the Santas Grotto will cause you to lose your room, so do not sell / recycle it or you will need to build a new one in order to get your room back.