Nothing will open it not even the expensive mystery key item.
Undertale the locked door in.
Come join the fun.
Glyde can be encountered in this room before fighting papyrus.
If you are defeated by papyrus instead of seeing a game over screen papyrus will capture you and lock you in the guest room.
To open this door you must dodge every name during the special thanks portion of the credits after a pacifist run.
It s not actually locked though and the bars are too wide to stop you from leaving.
That key will open the back door.
After that you go into sans room and will find another key on a box.
Undertale is about a child who falls into an underworld filled with monsters.
Repeat a few times to get a key to his room.
We re an unofficial community of fans and a showcase for undertale fanwork.
Then snoop around there to find an another key that unlocks a hidden door behind the house.
The mysterious door is an area found in snowdin forest south of the right side of the room with the icy x s and o s puzzle.
There is no other way to enter this building.
In the nintendo switch version examining the door leading to mad mew mew in the dog shrine before it is unlocked yields a message saying that the door is locked by a mysterious seal as an ominous piano jingle is heard.
Anyone that s started up undertale for the first time will encounter a mysterious locked door early in the game s snowdin area.
Don t worry though he gives you a nice bed and some food.
Undertale by indie developer toby fox is a video game for pc ps4 vita and switch.
By the way there s two other keys that you might want to check out if you already haven t.
The door which bears the delta rune is surrounded by glowing mushrooms and floating particles.
Save before talking to sans at the end then reload.