This is a sub-page of Undertale.
Undertale has a number of unused rooms, ranging from simple testing rooms, to just plain creepy stuff. Most of these rooms require Debug Mode to be enabled, otherwise the Annoying Dog error screen will appear.
- 1 room_gaster
- 2 room_2
- 3 TESTROOM
- 4 room_water_redacted
- 5 room_water13
- 6 room_overworld
- 7 bullettest
- 8 room_spritecheck
- 9 room_fire4
- 10 room_fire10_old
- 11 room_fire10A_old
- 12 room_tundra_placeholder
- 13 room_ruins12B_old
- 14 room_tundra_rollsnow
- 15 room_water7_older
- 16 room_meetundyne_old
- 17 room_water_mushroom
- 18 room_monsteralign_test
The room displays a message in the Wingdings font, while the sound ''mus_smile'' is played. The decoded message reads:
ENTRY NUMBER SEVENTEEN DARK DARKER YET DARKER THE DARKNESS KEEPS GROWING THE SHADOWS CUTTING DEEPER PHOTON READINGS NEGATIVE THIS NEXT EXPERIMENT SEEMS VERY VERY INTERESTING ... WHAT DO YOU TWO THINK?
A room that displays several sprites of the enemy Froggit before drowning the entire screen in red.
A grey room most likely used to test out the dialogue boxes in the game. Along with the three empty dialogue boxes, some text appears on the left and middle dialogue boxes respectively that read:
La, la. Time to wake up and smell the pain. Though.... It's still a little shaky. fhuehfuehfuehfuheufhe
In-game, the word "smell" is displayed in red text. In at least earlier versions of the game, the first line can occasionally appear elsewhere due to a glitch.
TestMonster and its cohorts draw near!
It should be noted that the text is not correctly formatted for the boxes, as the left text goes out of right side of the box, and the middle text goes straight down out of the box.
An empty, black room with nothing but an NPC in the center. Speaking to the NPC shows the following dialogue in the Wingdings font:
Leaving the room will lead to the "Sound Test" room.
A room that uses many of Waterfall's overworld assets, presumably for testing.
A black room with strange NPCs that move around the room. The NPCs appear to be falling lava streams with faces. This room also has collision boxes, a Flowey dialogue trigger, and a door to room_overworld_3, which is mostly just black space. The Flowey dialogue triggers a battle transition and a botched Toriel dialogue box. The player is then able to move the SOUL around freely. The Game Over theme, "Determination", plays in the background, but triggering Flowey's dialogue will cause "Your Best Friend" to overlap the music.
A battle against a Froggit that seems to be used to test the bullets sent by enemies in the game. The SOUL also seems to have a strange red and green ray/light effect emitting off of it. Many pellets will spawn at the bottom of the screen before rising up to the top. The game will crash shortly after.
A grey room that was obviously used to check the sprites used in-game. The game will display every single sprite in the game in rapid succession. Strangely, a sprite for the head of Undyne the Undying loads on the screen, but never changes, moves, or disappears. Pressing space while in debug mode allows the player to change to the next room.
A room that was presumably meant to be used as an area for Hotland. The room even plays the Hotland overworld theme, "Another Medium". However, the room seems to use floor assets from Waterfall. The room also contains direction vents that carry the player to the right. These vents were probably used for testing purposes. This room cannot be accessed unless "flag 367" is disabled. Otherwise, the game will crash.
Another room that tests assets exclusive to Hotland, while still using some of Waterfall's assets. The room contains a wave-shaped conveyor belt path that leads to another section of floor. Falling off the conveyor will take the player to room_fire10A_old.
This room contains a wide, straight conveyor belt path leading to the right and a bowl of dry dog food. Along with these are an Echo Flower next to the conveyor path, and a door on the other side that takes the player back up to room_fire10_old. Interacting with the Echo Flower will only write "Error!"
A room that appears to be used to test assets in Snowdin. The room is filled with tiles of ice and snow.
A simple, non-detailed purple room with a pedestal actor that dispenses Rock Candy, an item which can't be obtained anywhere else. Given the room's layout and name, it's likely this room was replaced with the Spider Bake Sale after Muffet was implemented into the game (apparently, rather early on).
A room that uses Snowdin's assets and contains a unique snowball object that can be made larger by rolling it, unlike the one that is used in-game. Presumably used for testing the snowball physics.
A room that was likely meant to be used in Waterfall. This room appears to use many assets from Waterfall such as lanterns, an Echo Flower, and... well... water. Among these though, are a few odd entities that also appear. There are poorly-drawn torches that are lit up and make a sound effect when interacted with, similar to the mushrooms found in Waterfall. Lighting all the torches triggers an invisible path with poorly-drawn guiding lights. Judging by the low quality of these entities, it's likely that these were either used as placeholders, or for testing purposes. The sign on the north wall has no dialogue assigned to it, so it will do nothing except create a text box that immediately closes.
An older version of the room where the player is introduced to Undyne for the first time. However, there are certain Waterfall assets scattered around. There's even the bunny guy and devil NPCs from Snowdin in the room. The player can talk to these as normal. Walking further right into the boards triggers the scene with Papyrus and Undyne, although they are misplaced in the boards in the middle, causing Undyne to be overlapped for the entirety of the scene. Papyrus retains his existing dialogue from the game.
A small room that uses Waterfall's assets. The only entities in the room are a crystal and an NPC that uses unique dialogue. When talked to, the NPC states:
You... You came from outside, didn't you? People like you are so rare... Please! Stranger! Tell me about outside...? (Yes/No) [IF NO] Is everyone out there like you? How terrible. [IF YES] Huh? "SURFACE"? What do you mean? I just meant outside this room. If you haven't noticed, my mycelium have bound me to the ground. Please! Stranger! I'll make this simple. I've spent my whole life in the same spot, in the same room. But I've long wondered what lies inside the room to the right. Long I've fantasized about entering, and changing my scenery...No... Changing my LIFE! Please. Go and tell me what's inside. [ON RETURN] Oh! You're back! How's the room? (Different/Same) [IF DIFFERENT] Oh, that's a relief!That's all I need to continue my fantasies. Thank you, stranger. [IF SAME] So it's the same. The same...Same...OK.
Presumably the dancing mushroom in Temmie village was originally planned to be used here.
A black room with a Memoryhead enemy that disappears. Likely used to test the alignment distortion used for that enemy.