Unused Content

In Undertale Yellow's game files, some unused content can be found left over. This article aims to document this content.

Unused Items

Toy Knife

The Toy Knife has weapon stats left over, and is in the game's debug menu as an available item. Like in Undertale, it's programmed to grant 3 AT points (whereas the Toy Gun and Wild Revolver grant 0), and has its slashing attack bar left in the code.

However, when used in practice, the attack bar goes unused, and instead is skipped in favor of an immediate "Inf" damage attack. This is a general failsafe used for all invalid weapon IDs.

Golden Scarf

Golden Scarf is an unused item accessible through the game's debug menu alongside Super Ammo. It is the best accessory in the game, giving a boost of 25 DF. Its flavor text when checked is "It's emitting a violently golden shine." and when used is "You put the Golden Scarf on. Your tremendous taste for fashion makes monsters go easy on you." It sells for 100G.

Super Ammo

Super Ammo is an unused item accessible through the game's debug menu alongside Golden Scarf. Despite its check text claiming that it is supposed to increase AT by 15, more than any other ammo in the game, it does not actually increase AT at all. Its flavor text when checked is "Regular toy gun ammo sold at your favorite convenience store. Boasts a "Premium" sticker on the top of the packaging." and when used is "You load the Super Ammo. Your gun now feels lighter than your conscience." (referencing Rubber Ammo's flavor text). It sells for 100G.

Homemade Cookie

Homemade Cookie (shortened as "Cookie") is an unused consumable item which restores 20 HP. Its flavor text when checked is "A little burnt on one side, but looks yummy anyway." and when used is "You scarf down the Homemade Cookie.".

Unused Dialogue

Unused Ceroba TALK line

In the room immediately after meeting Axis, Ceroba's talk dialogue is bugged, leading to two lines being unused. This is due to a "Break" being placed in the wrong spot, resulting in code from the next room being pulled.

So Axis is completely artificial intelligence? Well... artificial at least. Still, unemotional as he may be... The fact he so closely resembles life is impressive.

Intended dialogue (Talk 1)

Keep a move on, Clover. Well... artificial at least. Still, unemotional as he may be... The fact he so closely resembles life is impressive.

Bugged dialogue (Talk 1)

The second Talk also mistakenly has the code from the next section copied into it, resulting in the bug occurring twice.

Standing around won't get us to Hotland. Come on.

Intended dialogue (Talk 2)

Keep a move on, Clover. Come on.

Bugged dialogue (Talk 2)

TALK lines from unused rooms

Some unused older version of rooms left in the game's code still have "talk" dialogues implemented for them. Seemingly, when the rooms were replaced, these lines were not applied to the newer versions of the rooms, leaving them unused.

I have no clue where we're headed. I'm so unfamiliar with this place, it might as well be the Surface. Doing a great job of helping you, I know.

Martlet in rm_dunes_35, an old unused placement of Café Dune

Let's move.

Ceroba in rm_steamworks_07, an old version of the first steam vent dodging room

Unused Characters

Sans

A few sprites for Sans the Skeleton from Undertale appear. These include his left and up walk sprites, though the right and down sprites were not included, and three dialogue portraits: regular, looking sideways, and winking.

His associated talk sound, font, and strings related to his notable skull-like laser guns (Gaster Blasters) can also be found. Additionally, Sans-related content still appears in the final game, as the lake in rm_snowdin_10_yellow is known as obj_sans_lake.

He was presumably meant to appear somewhere in the Wild East, as his textures appear in the "Wild East" Texture Group.

Mettaton

Unlike Sans, no Mettaton sprites were left in the files. However, two scripts for Mettaton talking are left over. Mettaton's talk sounds are referenced but aren't actually included in the files. There are also unused strings referencing mus_mettatonbattle and mus_mettaton_ex.

Undertale Customs Leftovers

Ms. Mettaton

An unused fight can be found for someone named Ms. Mettaton, appearing to be a leftover from Undertale Customs, which Undertale Yellow's engine is built from. Her fight will only generate with the global.game_mode variable set to Customs, rather than Yellow.

Her attacks use the Blue SOUL mode. There are also unused strings referring to "Ms. Mettaton EX", and various sprite names.

Craniex

Like Ms. Mettaton, this is most likely unused data leftover from Undertale Customs. All sprites and associated audio files have been removed, alongside most scripts, however Craniex's talk script is still in the code, alongside the names of his attacks.

Unused Mechanics

SOUL modes

Data exists for the Blue, Purple, and Green SOUL modes from Undertale, and an unused variant of the Yellow SOUL, alongside unused sprites for Red and Blue SOULS. The Blue SOUL appears to be a leftover from the unused Ms. Mettaton fight, as it's referenced in her attack code. By editing an enemy's start_enemy_attacking code, it's possible to spawn the Blue SOUL, complete with three different directions; The standard 'Down' rotation crashes the game, due to an error in the control code.

Internally, Clover is considered to have the Red SOUL in most fights, but has an override in the SOUL sprite data to change the sprites to yellow. This override also applies to the Blue SOUL. The SOUL mode variable is only used by El Bailador in the final game.

Unused Attacks

Unused Bowll attack

Bowll has an unused fourth attack, "Bowll Test Song", which uses the Yellow Rhythm SOUL mode. As Bowll is immediately before El Bailador in the attack list, it's likely this was used to test El Bailador's attacks before the character was implemented.

The attack calls the same attacks El Bailador uses.

Unused Flowey Phase 1 attacks

The 1st phase of Flowey's boss battle has a few unused attacks.

Shoebox

This attack consists of shoes dropping from a shoebox, a group at a time, in a random order. It's theorized that this attack might have been used if you killed Martlet, due to its similarities to one of her attacks. It could also be a reference to the shoebox with "kids shoes in a disparity of sizes" in Toriel's house, because Clover, Flowey and the 5 humans all have a connection to her.

Audience

This attack would hide all of the battle UI except the bullet board, and show a sketch of a crowd under it. Afterwards, a small box will show at the top of the board that would say HATE, then flowers would start being thrown at the player.

There's also a JOY variant of this attack, however, other than a few associated graphics, this attack's data has been completely removed.

Unused Graphics

Unused Polygonal Flowey sprites

The sprites for the Polygonal phase of the Flowey battle include two unused images of himself glitching out in an erratic manner. Their intended usage is currently unknown, but it is likely they were used whenever they got damaged.

• 
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Unused Ceroba Ketsukane portraits

Some unused dialogue portraits for Ceroba. It's unclear where, if anywhere, these were planned to be used.

• 

  A portrait of Ceroba grinning

• 

  A derpy face, known as spr_portrait_ceroba_wat internally.

Bartender

An unused variation of Dina's design with a pink color palette.

• 

  The unused Bartender's overworld sprite.

• 

  The Bartender's leaning sprite.

Unused Flags

Hotland Genocide flags

Hotland appears to have once been planned to be a fully fleshed out area, as opposed to only a brief visit. Leftover data for Genocide's kill area, area 5, can be found in scr_determine_world_value_yellow, although only the first room of UG Apartments is considered part of this area. The unused global.geno_complete flag for Hotland is also present in the code, set in the scr_initialize script, and can be changed in the game's save data, but is never read by the game.

It's likely the expanded Hotland was cut early in development, as it lacks a large amount of required data, and doesn't have any associated kill count data.

Altered Dalv farewell speech

If Clover attacks Dalv during his fight and then spares him, Dalv is meant to have altered dialogue in his farewell speech to Clover where he nervously wonders if friends outside will also hurt him. Additionally, instead of clearing the gateway to Snowdin with his bare hands, he zaps the obstacles with a lightning bolt. These altered details are unused due to the flag controlling them never properly being set.

Unused Music

dalv_diary.ogg

An unused music track found in the game's files. Judging by the song's name, this was likely intended to be used when reading Dalv's diary entries.

mail_jingle_alt.ogg

An unused sound effect found in the game's files. Judging by its name, this seems to be an alternate version of the jingle heard when interacting with a UGPS sign. This jingle sounds very similar to Your Reality from the game Doki Doki Literature Club.

micro_temperature.ogg

An unused music track found in the game's files. Judging by the song's name and the leitmotifs present, this seems to be a scrapped track for the Golden Coffee room.

lounging_around.ogg

An unused music track found in the game's files that seems to be a beta/alternate version of Relaxation.

pipin_hot_yellow.ogg

An unused music track found in the game's files that seems to be a beta/alternate version of Honeydew Cabin.

cafe_arcade.ogg

An unused music track found in the game's files that seems to be either a beta version of ラブ･ブラスター!, or a scrapped theme for another arcade game in the Café Dune. Alternatively, it may have been intended to fade in dynamically when approaching the arcade machines, as seen with Mining Co-ncussion.

trampled_flowers.ogg

An unused music track found in the game's files that seems to be a beta/alternate version of TENTH LEVEL LOCKDOWN.

mothers_love_temp.ogg / unforgiving.ogg

A variant of A Mother's Love. Based on the name, this was likely a placeholder until the final theme was made.

A duplicate file, named "unforgiving.ogg" is also present. Given the name, this was likely a placeholder theme for Ceroba Ketsukane's fight in the Genocide Route, before being replaced with Trial By Fury.

final_stand.ogg

Appears to be an unused theme for Martlet. Given the name, this was likely meant to play in her Genocide Route fight, possibly for an unused phase or as an early version of Retribution. It features leitmotifs from Determination.

Unused Cutscenes

obj_cutscene

When spawned in, if you interact with a Starlo NPC, a cutscene will start which has the Starlo NPC look up, wait 2 cutscene frames, and then look down and say:

• This is really bad.
• I'm a fake test Starlo.
• But I won't leave
  it this way!

The cutscene ends with a dialogue that is said by the narrator:

• (It doesn't have to be this way.)

obj_cutscene2

The cutscene starts with a Ceroba NPC saying:

• I'm really sorry about
  the pops Starlo.
• When I see them...
  It's like a demon takes
  over.

Following this, a Starlo NPC says:

• Look at it from
  my point of view.
• You're looking forward
  to some pops after a
  long hard work day...
• Only to come home
  just to see...
• Just to see...

Then, the Starlo NPC looks to the left and says:

• Argh!
• I need time...

After that, the Starlo NPC walks off-screen. Due to an error, it doesn't switch to the next part of the cutscene. Via forcing the game to skip the "Starlo walking off screen" part, you can see the rest of the cutscene. The Ceroba NPC says:

• Loool worth it.
• Those pops were
  delicious.

Afterwards, the Ceroba NPC looks down and, with the "Blizzard Approaching" music playing, says:

• What are YOU looking
  at?!

obj_cutscene3

The cutscene starts with a Starlo NPC looking down, and then walking towards the y-coordinate 40 (presumably where Clover was meant to be). Subsequently, a battle with The Shufflers starts. This is the only cutscene that is reachable without modifying the data.win file, due to it already being in the room rm_debug.