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). When used in battle, it uses the Rubber Ammo's attack ring interface. 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 in battle is "You scarf down the Homemade Cookie." When used in the overworld, the game softlocks.

Unused Dialogue

Unused Ceroba TALK lines

In the room after escaping the basement, 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.

• Intended dialogue (Talk 1):
  • 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.
• Bugged 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.
• Intended dialogue (Talk 2):
  • Standing around won't get us to Hotland.
  • Come on.
• Bugged dialogue (Talk 2):
  • Keep a move on, Clover.
  • Come on.

Ceroba also has TALK dialogue for the Furnace before encountering Axis. Since she is shut off from Clover as soon as they enter, and the dialogue changes after defeating Axis, this is unable to be seen.

• Talk 1:
  • Was the only purpose of this furnace to dispose of garbage?
  • Why would they make it mandatory to walk through?
  • If you entered from Hotland...
  • ...the first thing you would smell is burning trash.
  • "Welcome to the Steamworks! It sucks here!"
• Talk 2:
  • This is way too hot, even for me.
  • Let's leave please.

Unused Ceroba Wild East dialogue

When talking to Ceroba while she is in by the movie tapes in the Wild East, one of her interactions is broken, beginning with the first line from the next interaction instead of the correct line.

• Interaction 3, intended dialogue:
  • Get out of my hair before you die of melodrama, will you?
  • I'm fine, trust me.
  • You need to focus on passing your training.
• Interaction 3, bugged dialogue:
  • You should get going. You don't wanna miss your next mission.
  • I'm fine, trust me.
  • You need to focus on passing your training.
• Interaction 4:
  • You should get going. You don't wanna miss your next mission.

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 newer rooms, leaving them unused.

• Martlet in rm_dunes_35, an old unused placement of Café Dune:
  • 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.
• Ceroba in rm_steamworks_07, an old version of the first steam vent dodging room:
  • Let's move.

Unused ACT flavor text

ACT descriptions in battle only display one box of text, but several battles are programmed with multiple. As a result, these second lines for various ACTs go unused in-game.

• Spin, Starlo battle:
  • You spin your six-shooter several times to intimidate Starlo.
  • He instead seems impressed.
• Glare while trapped, Starlo battle:
  • You narrow your eyes and everything becomes letterboxed.
  • Starlo doesn't know how this is possible.
• Glare while freed, Starlo battle:
  • You shoot a nasty look at Starlo…
  • He gives a worried face before forcefully glaring back.
• Stare, El Bailador Genocide battle:
  • You stare at the enemy with irritation.
  • He tries to act like he doesn't notice.
• Taunt, Axis Genocide battle:
  • You tell Axis that his time is up.
  • He chooses not to respond.
• Toughen, Axis Genocide battle:
  • You grip your sidearm with enmity…
  • Something stirs inside.
• Remind, Zenith Martlet phase 1 (A random one is picked):
  • A moment of remembrance is taken…
  • The bloodshed ends here.
  • A moment of remembrance is taken…
  • The mission is almost complete.
  • A moment of remembrance is taken…
  • They will be avenged.
• Focus, Zenith Martlet phase 2:
  • An end in sight.
  • Nothing else matters.

Unused Ceroba Steamworks dialogue

Ceroba is meant to have more dialogue reacting to the first Jandroid she and Clover encounter after the battle finishes. Due to an error in a variable being set, this never goes used.

• Ceroba, after the Jandroid is spared:
  • They're gone.
  • Sigh... This is so confusing...
  • I thought Axis said he was the last of his kind?
  • Wait... he introduced himself as "Model 014".
  • There must have been 13 other guard-bot prototypes.
  • Guess we're lucky only one functions, huh.
  • Still, this thing definitely wasn't a guard-bot...
  • We don't know how many other robot types are out there.
  • We'll figure it out in due time, I'm sure.
  • Just... be extremely careful.
• Ceroba, after the Jandroid is killed:
  • What are you thinking?!
  • I know they started the fight but we don't know the situation!
  • What if it was a glitch in their programming?
  • ...
  • These bots are antiques.
  • We have no right to destroy them, got that?
  • ...Sigh.
  • Why are we in this situation to begin with?
  • I thought Axis said he was the last of his kind...
  • Wait...
  • He introduced himself as "Model 014".
  • There must have been 13 other guard-bot prototypes.
  • I suppose only one is still functioning.
  • Still, this thing definitely wasn't a guard-bot...
  • We don't know how many other robot types are out there.
  • We'll figure it out in due time, I'm sure.
  • Just... don't do anything stupid.

Unused battle quotes

In the buildup to the end of the first phase of Ceroba's True Pacifist battle, she has one line of dialogue that goes unused due to there not being enough turns in the battle for it to appear. This line would have been accompanied by a screen shake and thudding sound effect.

• Die!! [Turn 9]
• Just die!!! [Turn 10]
• DIE!!!!! [Turn 11, unused]

Additionally, after sparing Ceroba the third and final time at the end of her True Pacifist battle, she has several lines of dialogue that usually go unseen due to Starlo cutting her off after a few seconds. While all of this dialogue can seen in-game by mashing her text, it is unreadable without going frame by frame.

• Why...?
• You...
• You don't understand.
• This is irreversible!
• Everyone knows what I've become!
• Living... after what I've done...
• I...

Jandroid is meant to have quotes in a duo battle with Goosic, as well as ACT quotes when their HP is low. These go unused.

• Jandroid, with Goosic (A random one is picked):
  • goNNA woRK so MucH HARDER!!!
  • YEAH yeAH!! puMP IT UP!!!!
• Jandroid, Question, Low HP:
  • W//what was_That? /(
• Jandroid, Clean, Low HP
  • St_amwrrks Need_/ scruBbed 0
• Jandroid, Analyze, Low HP
  • AaAAaoo/aa/. Bzzt.’"<<<

Goosic is also meant to have more dialogue in response to ACTs after Clover picks Needle. This dialogue is never used.

• Goosic, Vibe (A random one is picked):
  • Okay, yeah ! I see you !
  • Oh, now THIS is groovy !
• Goosic, Ignore (A random one is picked):
  • Come o-on, relax a l-l-little .
  • N-No need to be bashful, buddy .
• Goosic, Needle (A random one is picked):
  • Don't k-kill the mood :)
  • I like th-this one :)

Unused battle flavor text

Goosic is meant to have a special flavor text after selecting Needle which goes unused.

• Goosic is liking the new tune.

In her Genocide Route battle, Ceroba has several unused lines of flavor text.

• Neutral flavor text:
  • Ceroba's focus grows stronger.
  • The echoes of Ceroba's magic ring out.
  • No mercy.
• Neutral and encounter flavor text:
  • The atmosphere chills with ire.

Starlo's battle also has unused flavor text.

• Neutral flavor text, tied up:
  • You hear nothing but gunshots, whip cracks, and a mighty acoustic guitar.
  • A gust of sand momentarily blinds you.
• Neutral flavor text, freed:
  • You begin to sweat under the immense heat.
  • You hear Starlo talking to himself under his breath.
• Neutral flavor text, either:
  • Starlo digs his spurs into the sand, standing strong.

Unused Vendy text

Vendy's "Creator" talk option with Steamworks ID is missing the last line.

• Intended dialogue:
  • ...salesman, mailsman, snailsman, beekeeper, birdkeeper, veteran, veterinarian, electrician, beautician, magician, war criminal, banker, pranker, fish-tanker, and…
  • ...3% shareholder in the government.
  • What a guy!
• Bugged dialogue:
  • ...salesman, mailsman, snailsman, beekeeper, birdkeeper, veteran, veterinarian, electrician, beautician, magician, war criminal, banker, pranker, fish-tanker, and…
  • ...3% shareholder in the government.

They also have unused dialogue for purchasing an item without Steamworks ID. This goes unused, and buying an item will use the same dialogue as with ID.

• Intended dialogue:
  • Curse my programming.
• Bugged dialogue:
  • Item dispensed!

Unused Characters

Sans

A few sprites for Sans the Skeleton from Undertale appear. These include his left and up walk sprites 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.

While he does not appear in the final game and was never intended to, Sans was included in a playtest build of the game. He was hidden for a joke, and only a couple playtesters found him. He may have been placed 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.

• 
• 

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 Tracks

Main article: Unused Music Tracks

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.