Inaccessible Rooms

In Undertale ' s game files, the player cannot access some rooms by conventional means. If the player attempts to access these inaccessible rooms, the "Dogcheck" value will return out of range and cause the Annoying Dog to appear in the middle of a black screen while "Sigh of Dog" or "Dance of Dog" plays.

The rooms below are listed in numerical order.

Room 123
Room 123, also known as room_water_prebird, is between room_water_farm and room_water_shop. Its name suggests that Toby Fox may have planned to place it before the Bird That Carries You Over A Disproportionately Small Gap. The room has a thin stretch of land surrounded by water on two sides. Grass covers the path, and the protagonist can talk to two NPCs hidden within it. One NPC remarks that they love to catch bugs in their spare time, and the other one asks the protagonist to do something about their friend, who the NPC says has a creepy smile. If the protagonist speaks to the second NPC again, the NPC asks where their friend went. Exiting the area on the left or right crashes the game. This could be the bug catching spot Toriel mentions when you talk to her in her home.

Room 264
Room 264, otherwise known as room_gaster, is black and displays white text in a pixelated Wingdings font. The player hears a distorted sound (mus smile or an altered Muffet's laugh) as the text progresses. Once the message ends, the screen turns black for a moment before the game closes. 

Room 267
Room 267, also known as room_2, displays three Froggit sprites before printing the screen red and loudly playing the enemy defeated sound. After a while, it will crash the game.

Room 271
Room 271, also known as TESTROOM, is gray and has three text bubbles next to one another. Text within the dialogue boxes sways. "* Testmonster..." is displayed vertically beneath the second dialogue box.

No more text prints after the last dialogue.

In the Undertale Demo, this room replaces room 326 if the SAVE is invalid.

Room 272
Room 272, also known as room_water_redacted, is black and has an NPC in the middle. As the protagonist approaches, the NPC fades and, when spoken to, says "* [redacted]" in Wingdings. This NPC represents one of two theorized sprites for W. D. Gaster. If the protagonist leaves through the south exit, they enter the sound test room, room 270. One of the four playable songs in this room is "Gaster's Theme"; when the protagonist attempts to exit the room, the game crashes. If the protagonist chooses to play "Gaster's Theme," they can select no other song.

Room 273
Room 273, also known as room_water13, uses Waterfall sprites and has a long narrow pathway that leads to a large area of land covered in tall grass. The protagonist can find Bridge Seeds in the grass and can use these seeds to reach a pathway on the right side of the room. The exit here leads to room 274.

Room 274
Room 274, also known as room_overworld, is black with NPCs that appear to be lava streams with stoic faces, similar to the protagonist's expression, while Determination is playing. In the game files, these sprites are named " " Talking to these NPCs crashes the game. There are two dialogue triggers that the protagonist can activate: Toriel's and Flowey's. The Toriel dialogue is almost identical to her initial dialogue when the protagonist meets her in-game; the only differences are that "TORIEL" is in blue and "RUINS" is in red.

The Flowey dialogue triggers a battle with him, and dialogue from a Neutral Route ending loops while "Your Best Friend" blares. The game crashes if the protagonist attempts to exit the dialogue.

Room 275
Room 275, also known as room_overworld3, is mostly a black room.

Room 276
Room 276, also known as bullettest, is a Froggit battle with many pellets coming from the bottom of the screen while Anticipation plays. The SOUL emits green and red rays while the bullets avoid it. The game crashes shortly after entering this room.

Room 277
Room 277, also known as room_water3, seems to be a black room. It is probably going to be a room for the Waterfall area.

Room 287
Room 287, also known as room_spritecheck, is gray and displays every single sprite in a rapid succession. After Undyne the Undying's head loads, the center-most sprite becomes a static sprite, though the others still cycle.

Room 296
Room 296, also known as room_fire4, uses Hotland sprites and Waterfall floor sprites. It has a path that goes up and then turns right, and steam vents line the path. The protagonist can access these vents by walking through the wall. "Another Medium," a reoccurring song in Hotland, plays in this room. Going below sometimes loads room 294 (Photoshop Flowey's battle, which will crash the game), going right will also crash the game.

Sometimes, a dialogue box displays the Undertale prologue and activates a fleeable Mettaton battle.

Room 297
Room 297, also known as room_fire10_old, uses Hotland sprites and conveyor belts line a pathway that the protagonist must cross to get to the other side. If the protagonist falls off a conveyor belt, they will find themselves in room 298. The exits on the right and left of the room are nonfunctional.

Room 298
Room 298, also known as room_fire10A_old, uses Hotland sprites and contains two platforms, one at each end of the room, that conveyor belts link. A single Echo Flower located in the middle of the room says only "* Error!" The left side of the room has a door that leads to room 297, and the other end of the room has a bowl of dog food. The protagonist can find this same bowl in Papyrus's shed.

Room 299
Room 299, also known as room_tundra_placeholder, uses Snowdin sprites and consists of an ice puzzle. If the protagonist attempts the puzzle, the ice pushes the protagonist backward when touched. There is nothing located at the end of the puzzle, and this room does not connect to any other room.

Room 300
Room 300, also known as room_ruins12B_old, uses Ruins sprites and is similar to room 13, the room where the protagonist can find Monster Candy. Instead of Monster Candy, this room has Rock Candy, and the protagonist can only hold one Rock Candy at a time; to take another, the protagonist needs to eat or drop the piece of Rock Candy that they currently have.

Room 301
Room 301, also known as room_tundra_rollsnow, has a small snowball whose mechanics are similar to the Ball Game in Snowdin Forest. If the protagonist pushes the snowball, it gradually grows until it reaches maximum size. This room does not connect to any other rooms.

Room 302
Room 302, also known as room_water7_older, uses Waterfall sprites, and the game will crash when entered unless the file " " is edited or deleted. This room has a single Echo Flower that says "* Error!" and several torch-like objects that may be placeholders due to their poor quality. The tops of these objects combust when the protagonist interacts with them. This room may represent an unfinished puzzle similar to the torch puzzles in The Legend of Zelda. Leaving this room crashes the game.

Room 303
Room 303, also known as room_meetundyne_old, is an old version of the room where the protagonist initially meets Undyne. There are some NPCs and a sign that functions as an Echo Flower; it reiterates the last line of dialogue that the protagonist heard from the NPCs. This room also has the scene in which Papyrus talks to Undyne and uses the same dialogue as the final version of the room. After Papyrus talks to Undyne, Monster Kid's dialogue displays even though they are not visible in the room. The right exit leads to room 304.

Room 304
Room 304, also known as room_water_mushroom, has an NPC that asks the protagonist what the "outside" is like. The NPC then asks the protagonist to investigate the room to the right and return to tell him what they found. His dialogue is similar to Ragel's; he talks about being unable to explore because he is rooted to the ground. The bottom exit connects to room 303.

Room 305
Room 305, also known as room_monsteralign_test, is black and has a Memoryhead that disappears.

Room 306
Room 306, also known as room_battle, is the battle room. While the battle scene is used in-game, this room does not contain a monster because it lacks data for it and is not accessed by the game normally.

Room 321
Room 321, also known as room_empty, is a black room.

Room 326
Room 326, also known as room_of_dog, is the Annoying Dog error room if the SAVE is invalid. The unused soundtrack mus sigh of dog or mus dance of dog plays in this room.

In the Undertale Demo, room 271 replaces this room.

Room 327
Room 327, also known as room_quizholder, is a black screen with Mettaton and Alphys, as seen in Mettaton's quiz show. Mettaton waves while Alphys looks on nervously; the player can do nothing in this room.

Room 328
Room 328, also known as room_friendtest, is gray and was used to test the scene before the Asriel Dreemurr battle in the True Pacifist Route. It includes the final dialogues and battle sprites of all characters. Random sprites flash and scroll during the scene, including the sepia Asriel images Temmie Chang created. The game crashes after Flowey delivers the line "I'll keep you here no matter what!"

Room 329
Room 329, also known as room_bringitinguys, is black and was used to test the scene before Asriel's battle where the monsters encourage the protagonist to keep fighting. It includes the final dialogues and battle sprites of all monsters that enter during this scene; the main cast is absent. The game does not progress further than this scene.

Room 333
Room 333, also known as room_asrieltest, is black and was used to test Asriel Dreemurr's "God of Hyperdeath" animation. The SOUL is a placeholder sprite and there is no bullet board; the SOUL can move freely around and behind Asriel's battle sprite.

Asriel floats up and down as he does in-game, but he does not shake his head. After a few minutes, Asriel moves from side to side in an arc pattern as his rainbow sprites display.

Room 334
Room 334, also known as room_afinaltest, was used to test Asriel Dreemurr's "Angel of Death" animation. The SOUL is the same placeholder sprite seen in room 333. The SOUL can move freely around the screen and is always in the foreground.

Room 335
Room 335 is supposed to load the name screen. However, it will crash the game when loaded.